An ultrasonic plasticizing micro-injection molding device and method based on a composite dynamic force field

Abstract

The present invention discloses an ultrasonic plasticizing micro-injection molding device and method based on a composite dynamic force field, which includes a moving mold assembly, a fixed mold assembly, an ultrasonic vibration assembly, and a mechanical vibration assembly arranged coaxially; a moving mold hydraulic assembly controls the axial movement of the moving mold assembly, a driving assembly one controls the axial movement of the ultrasonic vibration assembly, a driving assembly two controls the axial movement of the mechanical vibration assembly, and the ultrasonic tool head of the ultrasonic vibration assembly passes through the moving mold assembly; the moving template and the fixed template are closely attached when the mold is closed, a through hole and a cavity are formed at the center of one side of the fixed template, a circular tube is inserted into the other side, and the circular tube and the through hole form a plasticizing cavity, and the feeding assembly and the plasticizing cavity are communicated through a feeding port; the ultrasonic tool head, the vibration gasket of the mechanical vibration assembly, and the plasticizing cavity are coaxial and have the same diameter. The present invention introduces a dynamic force field formed by the combination of ultrasonic vibration and mechanical vibration into injection molding, improves the plasticizing efficiency and stability, reduces molding defects, and improves the filling quality and precision of products.

Description

Technical Field

[0001] The present invention relates to the field of micro-injection molding, and particularly to an ultrasonic plasticizing micro-injection molding device and method based on a composite dynamic force field. Background Art

[0002] Polymer micro-parts play an important role in the field of micro-electromechanical system applications due to their advantages such as low cost, corrosion resistance, impact resistance, and light weight. The micro-nano manufacturing technologies for polymers mainly include lithography technology, electrical discharge machining, hot embossing, and micro-injection molding. Compared with other micro-nano manufacturing technologies, the micro-injection molding technology has the advantages of low cost, high efficiency, and high precision. Traditional micro-injection technology uses a screw or a plunger for plasticization, which has the disadvantages of high raw material waste rate, difficult filling, poor plasticization effect, high energy consumption, and high production cost and equipment cost.

[0003] Technicians introduced ultrasonic waves into the micro-injection molding technology, directly plasticized the polymer using ultrasonic waves, and no longer used a screw or a plunger for plasticization, thus avoiding various drawbacks of traditional micro-injection molding. The polymer melt plasticized by ultrasonic waves has good fluidity, which is beneficial to the filling of the melt in the mold cavity; it can achieve plasticization and molding according to quantity, minimizing the waste of raw materials to the greatest extent; it has low requirements for injection pressure and injection speed, greatly reducing energy consumption and the manufacturing cost and usage cost of the molding device.

[0004] The existing ultrasonic plasticizing micro-injection molding technologies can be divided into two categories. The first is "plasticizing while injecting", that is, the plasticizing cavity is connected to the mold cavity, and while ultrasonic plasticization is carried out, an ultrasonic tool head or a plunger is used to inject and fill the melt into the cavity. This method mainly has the disadvantages of low service life caused by serious wear of the ultrasonic tool head and the risk that unplasticized impurities easily enter the cavity, resulting in product quality defects. The second is "plasticizing first and then injecting", that is, the injection stage does not require the participation of ultrasonic action of the tool head, and the polymer material is plasticized under a lower pressure, avoiding the risk of unplasticized impurities entering the cavity. However, this method has the disadvantages of complex equipment structure and high control requirements.

[0005] In addition, both of the existing two ultrasonic plasticizing micro-injection device structures have the problem that the temperature field distribution in the plasticizing cavity is uneven during the ultrasonic plasticization process, resulting in uneven plasticization and easy occurrence of charring phenomenon, which further limits the maximum single plasticization amount of ultrasonic plasticization and cannot meet the requirements of industrial large-scale production. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the present invention proposes an ultrasonic plasticizing micro-injection molding device and method based on a composite dynamic force field. The device of the present invention has high plasticizing efficiency, stable plasticizing performance, and high quality precision of the molded product.

[0007] The specific technical solutions are as follows:

[0008] An ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field, comprising: a feeding assembly, a moving die assembly, a moving die hydraulic assembly, a fixed die assembly, an ultrasonic vibration assembly, a mechanical vibration assembly, a driving assembly I, a driving assembly II, a measuring assembly, a temperature control assembly, a control system, and a bracket; the control system receives data from the measuring assembly and controls the feeding assembly, the moving die hydraulic assembly, the ultrasonic vibration assembly, the mechanical vibration assembly, the two driving assemblies, and the temperature control assembly;

[0009] The bracket includes a first vertical plate and a second vertical plate arranged parallel and opposite to each other. The fixed end of the moving die hydraulic assembly is fixedly connected to the first vertical plate, and its moving end is fixedly connected to the moving die assembly, controlling the axial movement of the moving die assembly; the driving assembly I is fixedly connected to the first vertical plate, on which the ultrasonic vibration assembly is fixedly connected and drives the ultrasonic vibration assembly to perform axial movement; the ultrasonic tool head of the ultrasonic vibration assembly is coaxial with the moving die assembly and passes through the moving die assembly; the moving die assembly is parallel to the first vertical plate;

[0010] The fixed die assembly includes a fixed template and a fixed die base plate arranged parallel and coaxial. The fixed die base plate is fixedly connected parallel to the second vertical plate; one end of the driving assembly II is fixedly connected to the second vertical plate, and the other end passes through the window at the center of the fixed die base plate and is fixedly connected; the driving assembly II is fixedly connected with the mechanical vibration assembly and drives the mechanical vibration assembly to perform axial movement; the moving die assembly is closely attached to the fixed template during mold closing. A through hole with the same diameter as the ultrasonic tool head is opened at the center of the fixed template. A cavity communicating with the through hole is provided on the surface of the fixed template facing the moving die assembly. A circular tube with the same inner diameter as the through hole is inserted at the center of the surface facing the fixed die base plate, and the circular tube is coaxial and communicates with the through hole. The formed cylindrical cavity is a plasticizing cavity; a feeding port is opened on the circular tube for communicating the feeding assembly and the plasticizing cavity, and the feeding assembly is used for quantitatively conveying polymer materials;

[0011] The ultrasonic tool head, the vibration gasket of the mechanical vibration assembly, and the plasticizing cavity are coaxial, and the diameter of the vibration gasket is the same as that of the plasticizing cavity; the ultrasonic tool head is used to generate high-frequency and low-amplitude vibrations, and the mechanical vibration assembly is used to generate low-frequency and high-amplitude vibrations;

[0012] The temperature control assembly includes a cooling water pipe and a heating coil. The cooling water pipe is arranged inside the moving die assembly and inside the fixed template, and the heating coil is arranged on the outer periphery of the circular tube; the measuring assembly is used to measure the temperature and pressure inside the plasticizing cavity.

[0013] Further, the ultrasonic vibration assembly includes: an ultrasonic generator, an ultrasonic transducer, an ultrasonic horn, and an ultrasonic tool head; the ultrasonic transducer, the ultrasonic horn, and the ultrasonic tool head are coaxially and fixedly connected in sequence, the ultrasonic transducer is coaxially and fixedly connected to the first driving assembly, and the ultrasonic generator is connected to the ultrasonic transducer; the ultrasonic generator is used to generate a high-frequency excitation voltage, the ultrasonic transducer receives the high-frequency excitation voltage and generates high-frequency vibration, and the ultrasonic horn is used to amplify the vibration and transmit it to the ultrasonic tool head.

[0014] Further, the mechanical vibration assembly includes: a vibration gasket, a vibration connecting rod, and a voice coil motor; the vibration gasket is coaxially and fixedly connected to one end of the vibration connecting rod, and the other end of the vibration connecting rod is coaxially and fixedly connected to the output shaft of the voice coil motor, and the voice coil motor drives the vibration connecting rod and the vibration gasket to perform mechanical vibration.

[0015] Further, the feeding assembly includes: a feeding cylinder, an electromagnetic ball valve, a weighing cylinder, a feeding valve plate, and a precision weighing sensor; the feeding cylinder is used to contain the polymer material, the weighing cylinder is tubular, coaxially installed at the lower end of the feeding cylinder and communicated with it; an electromagnetic ball valve is arranged between the feeding cylinder and the weighing cylinder to control the inflow of the polymer material; a feeding valve plate is arranged in the weighing cylinder, and a precision weighing sensor is arranged below the feeding valve plate; when the feeding valve plate is in the closed state, the precision weighing sensor weighs the polymer material loaded on the feeding valve plate; when the weight of the polymer material loaded on the feeding valve plate reaches the set value, the feeding valve plate opens, and the polymer material falls due to gravity, and the metered and weighed polymer material of the feeding assembly enters the plasticizing cavity through the feeding port.

[0016] Further, the moving mold hydraulic assembly includes: a hydraulic rod, a hydraulic actuator, and a hydraulic power unit; the hydraulic actuator and the hydraulic power unit are respectively fixedly connected to the first vertical plate, and the hydraulic power unit is connected to the hydraulic actuator to provide power for it; the hydraulic rod is coaxially installed in the hydraulic actuator to achieve expansion and contraction, and the top of the hydraulic rod is fixedly connected to the moving mold assembly.

[0017] Further, the moving mold assembly includes a moving template and a moving mold base plate arranged in parallel and coaxially. One side of the moving mold base plate is fixedly connected to the moving mold hydraulic assembly, and the other side is fixedly connected to the moving template, and the moving mold base plate is parallel to the first vertical plate; the moving template and the fixed template are closely attached when the mold is closed; installation holes are provided at the centers of the moving template and the moving mold base plate for installing the ultrasonic tool head; cooling water pipes are arranged inside the moving template.

[0018] Further, the first driving assembly includes: a first servo motor, a first speed reducer, two first driving wheels, a first conveyor belt, a first lead screw bearing, a first lead screw, a first lead screw nut, and an ultrasonic tool head push rod; the first lead screw bearing is fixedly installed through a through hole opened on the first vertical plate, and the first lead screw bearing is sleeved on the outer periphery of one of the first driving wheels; the first driving wheel is coaxially and fixedly connected to the first lead screw, a first lead screw nut meshing with the first lead screw is sleeved on the first lead screw, the first lead screw nut is coaxially and fixedly connected to the ultrasonic tool head push rod, and the ultrasonic tool head push rod is fixedly connected to the ultrasonic vibration assembly; the output shaft of the first servo motor is fixedly connected to the input shaft of the first speed reducer, and the output shaft of the first speed reducer is fixedly connected to the other first driving wheel; the two first driving wheels are connected by the first conveyor belt to achieve synchronous rotation.

[0019] Further, the second driving assembly includes: a second servo motor, a second speed reducer, two second driving wheels, a second conveyor belt, a second lead screw bearing, a second lead screw nut, a second lead screw, a slider, a slide rail, a support plate, and a voice coil motor push rod; one end of the support plate is fixedly connected to the second vertical plate of the bracket, and the other end is installed on and fixedly connected to a window opened at the center of the fixed mold base plate; a slide rail is fixedly connected to the support plate, a slider is installed on the slide rail, and the upper surface of the slider is fixedly connected to the mechanical vibration assembly;

[0020] The second lead screw bearing is fixedly installed through a through hole opened on the second vertical plate, and the second lead screw bearing is sleeved on the outer periphery of one of the second driving wheels; the second driving wheel is coaxially and fixedly connected to the second lead screw, a second lead screw nut meshing with the second lead screw is sleeved on the second lead screw, the second lead screw nut is fixedly connected to the voice coil motor push rod, and the voice coil motor push rod is fixedly connected to the mechanical vibration assembly; the output shaft of the second servo motor is fixedly connected to the input shaft of the second speed reducer, and the output shaft of the second speed reducer is fixedly connected to the other second driving wheel; the two second driving wheels are connected by the second conveyor belt to achieve synchronous rotation.

[0021] An ultrasonic plasticizing micro-injection molding method based on a composite dynamic force field is realized according to the ultrasonic plasticizing micro-injection molding device based on the composite dynamic force field, and includes the following steps:

[0022] Step 1, mold closing stage: the moving mold hydraulic assembly drives the moving mold assembly to move axially, so that the moving mold assembly is closely attached to the fixed template to complete the mold closing action; meanwhile, the first driving assembly drives the ultrasonic tool head to move axially, so that during the mold closing process, the position of the ultrasonic tool head and the moving mold assembly remains relatively stationary; after the mold closing action is completed, the moving mold hydraulic assembly stops working, and at this time, the end face of the ultrasonic tool head is located at one end of the plasticizing cavity;

[0023] Step 2. Feeding stage: The polymer material after being metered and weighed by the feeding component enters the plasticizing cavity from the feeding port. When the polymer material completely enters the plasticizing cavity, the feeding component stops working; when the polymer material completely enters the plasticizing cavity, the feeding valve plate is adjusted to the closed state; meanwhile, the driving component 1 drives the ultrasonic tool head into the plasticizing cavity and isolates the plasticizing cavity from the mold cavity.

[0024] Specifically, the feeding component meters and weighs the polymer material as follows: Open the electromagnetic ball valve to allow the polymer material to enter the weighing cylinder from the feeding cylinder and fall on the feeding valve plate. The weight of the polymer material entering is measured by a precision weighing sensor; when the weight of the polymer material reaches the plasticizing requirement, close the electromagnetic ball valve and open the feeding valve plate to allow the polymer material to flow into the plasticizing cavity due to gravity.

[0025] Step 3. Plasticizing preparation stage: The driving component 2 pushes the mechanical vibration component to move axially, initially compressing the polymer material by the vibration gasket and isolating the plasticizing cavity from the feeding port. At this time, a closed space is formed in the plasticizing cavity; the heating coil starts to preheat the plasticizing cavity.

[0026] Step 4. Plasticizing process stage: The ultrasonic vibration component starts to work, and the ultrasonic tool head generates high-frequency and low-amplitude vibrations and directly acts on the polymer material in the plasticizing cavity; meanwhile, the mechanical vibration component starts to operate, applying low-frequency and high-amplitude vibrations to the polymer material in the plasticizing cavity through the vibration gasket, so as to form a dynamic force field composed of the composite of ultrasonic vibration and mechanical vibration in the plasticizing cavity, and the polymer particles are continuously plasticized to form polymer melt.

[0027] The specific process of the ultrasonic vibration component working is as follows: The high-frequency excitation voltage emitted by the ultrasonic generator is transmitted to the ultrasonic transducer. Under the action of the inverse piezoelectric effect, the ultrasonic transducer generates high-frequency vibrations. Through the amplification of the ultrasonic horn, the ultrasonic tool head generates high-frequency and low-amplitude vibrations and directly acts on the polymer material in the plasticizing cavity; as the ultrasonic plasticizing continues, the pressure loss between the polymer particles gradually decreases, and the pressure value in the plasticizing cavity slowly increases. When the pressure value in the plasticizing cavity reaches the maximum, it is determined that the polymer material is completely plasticized.

[0028] Step 5. Injection stage: When the polymer is completely plasticized, the ultrasonic vibration component and the mechanical vibration component continue to work to maintain the applied composite dynamic force field; and the driving component 1 is activated to make the ultrasonic tool head move axially away from the plasticizing cavity to connect the plasticizing cavity with the mold cavity; the driving component 2 drives the mechanical vibration component to move axially towards the mold cavity to inject the polymer melt into the mold cavity.

[0029] Step 6. Pressure holding stage: When the polymer melt is completely filled into the mold cavity, the driving component 2 stops running, and the ultrasonic vibration component and the mechanical vibration component continue to work for a period of time for pressure holding, so that the polymer melt is fully filled in the mold cavity and surface defects of the product are avoided.

[0030] Step 7, Cooling and forming stage: The heating coil stops heating, and the ultrasonic vibration assembly and the mechanical vibration assembly stop working; Cooling water is introduced into the cooling water pipe to lower the temperature of the polymer melt and cool it into a formed product.

[0031] Step 8, Mold opening stage: The moving mold hydraulic assembly drives the moving mold assembly to move axially away from the fixed template. At the same time, the driving assembly 1 drives the ultrasonic tool head to move axially so that it remains relatively stationary with respect to the moving mold assembly.

[0032] Step 9, Ejection stage: The driving assembly 2 starts to operate, pushing the vibration gasket to move axially to eject the formed micro product; After the ejection is completed, the driving assembly 2 drives the vibration gasket back to the initial position before mold closing.

[0033] The beneficial effects of the present invention are as follows:

[0034] (1) The design of the device of the present invention introduces a dynamic force field composed of a composite of ultrasonic vibration and mechanical vibration into the entire injection molding process (plasticization, injection, and holding pressure). The structure is simple, the cost is low, and the control is convenient. In practical applications, for the plasticization process, the plasticization efficiency is higher and the plasticization is more uniform and stable; for the injection process, the material viscosity and the molding pressure are reduced, the filling time is shortened, and the molding defects are reduced; for the holding pressure process, the closing time of the gate is extended, and the filling quality and dimensional accuracy of the micro-nano product are improved.

[0035] (2) By controlling the moving mold hydraulic assembly and the driving assembly 1, the ultrasonic tool head makes a small axial movement in the initial stage of injection in the method of the present invention, realizing the decoupling of the plasticization stage and the injection stage, and extending the service life of the ultrasonic tool head; The mechanical vibration assembly and the driving assembly 2 are provided to increase the pulsating pressure during the injection process. Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the overall structure of the ultrasonic plasticizing micro-injection molding device with a composite dynamic force field in the embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the structure of the moving mold hydraulic assembly in the embodiment of the present invention.

[0038] Figure 3 It is a schematic diagram of the structure of the moving mold assembly in the embodiment of the present invention.

[0039] Figure 4 It is a schematic diagram of the structure of the ultrasonic vibration assembly in the embodiment of the present invention.

[0040] Figure 5 It is a schematic diagram of the structure of the driving assembly 1 in the embodiment of the present invention.

[0041] Figure 6 Explosion structure diagram of the fixed mold assembly in the embodiment of the present invention.

[0042] Figure 7 Structure diagram of the feeding assembly in the embodiment of the present invention.

[0043] Figure 8 Structure diagram of the mechanical vibration assembly in the embodiment of the present invention.

[0044] Figure 9 Structure diagram of the second driving assembly in the embodiment of the present invention.

[0045] Figure 10 Cross-sectional view of the structural relationship between the fixed mold assembly, the ultrasonic tool head, and the vibration gasket in the embodiment of the present invention.

[0046] Figure 11 Schematic diagram of the positions of the ultrasonic tool head and the vibration gasket in the plasticizing cavity at different molding stages in the embodiment of the present invention.

[0047] Figure 12 Flow chart of the molding method in the embodiment of the present invention.

[0048] Figure 13 Schematic diagram of the speed curve during the injection process of the vibration gasket in the embodiment of the present invention.

[0049] In the figure, feeding assembly 1, moving mold assembly 2, moving mold hydraulic assembly 3, fixed mold assembly 4, ultrasonic vibration assembly 5, mechanical vibration assembly 6, first driving assembly 7, second driving assembly 8, measurement assembly 9, temperature control assembly 10, control system 11, support 12;

[0050] Feeding barrel 101, electromagnetic ball valve 102, weighing barrel 103, feeding valve plate 104, precision weighing sensor 105;

[0051] Moving template 201, mounting hole 202, moving mold base plate 203;

[0052] Hydraulic rod 301, hydraulic actuator 302, hydraulic power unit 303;

[0053] Fixed template 401, fixed mold base plate 402, plasticizing cavity 403, feeding port 404, cavity 405, round tube 406;

[0054] Ultrasonic generator 501, ultrasonic transducer 502, ultrasonic horn 503, ultrasonic tool head 504;

[0055] Vibration gasket 601, vibration connecting rod 602, voice coil motor 603;

[0056] The first servo motor 701, the first speed reducer 702, the first driving wheel 703, the first conveyor belt 704, the first lead screw bearing 705, the first lead screw 706, the first lead screw nut 707, the ultrasonic tool head push rod 708;

[0057] The second servo motor 801, the second speed reducer 802, the second driving wheel 803, the second conveyor belt 804, the second lead screw bearing 805, the second lead screw nut 806, the second lead screw 807, the slider 808, the slide rail 809, the support plate 810, the voice coil motor push rod 811;

[0058] The temperature sensor 901, the pressure sensor 902;

[0059] The cooling water pipe 1001, the heating coil 1002. Specific embodiments

[0060] The present invention will be described in detail below with reference to the drawings and preferred embodiments. The objectives and effects of the present invention will become more apparent. The present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0061] As Figure 1 shown, an ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field includes: a feeding assembly 1, a moving mold assembly 2, a moving mold hydraulic assembly 3, a fixed mold assembly 4, an ultrasonic vibration assembly 5, a mechanical vibration assembly 6, a driving assembly one 7, a driving assembly two 8, a temperature control assembly 10, a control system 11, and a bracket 12. The bracket 12 includes two vertical plates and one horizontal plate. The two vertical plates are respectively fixedly connected to both ends of the horizontal plate, and the two vertical plates are placed in parallel. The temperature control assembly 10 includes a cooling water pipe 1001 and a heating coil 1002, and is used to control the temperature of the ultrasonic plasticizing micro-injection molding.

[0062] As Figure 2 shown, the moving mold hydraulic assembly 3 includes: four hydraulic rods 301, four hydraulic actuating devices 302, and a hydraulic power device 303. The hydraulic actuating devices 302 and the hydraulic power device 303 of the moving mold hydraulic assembly 3 are fixedly connected to the first vertical plate, and the hydraulic power device 303 is connected to the hydraulic actuating devices 302; the hydraulic rods 301 are coaxially installed in the hydraulic actuating devices 302 and can be telescoped under the action of the hydraulic actuating devices 302. The top ends of the hydraulic rods 301 are fixedly connected to the moving mold assembly 2. In the actual application process, the hydraulic power device 303 provides hydraulic power to drive the hydraulic actuating devices 302, and then drives the hydraulic rods 301 to move, and drives the moving mold assembly 2 to move axially to complete the mold opening and closing actions.

[0063] As Figure 3As shown in the figure, the moving die assembly 2 includes a moving die plate 201 and a moving die base plate 203 arranged in parallel and coaxially. One side of the moving die base plate 203 is fixedly connected to the hydraulic rod 301, and the other side is fixedly connected to the moving die plate 201, and the moving die base plate 203 is parallel to the first vertical plate; mounting holes 202 are provided at the centers of the moving die plate 201 and the moving die base plate 203 for cooperating with the ultrasonic vibration assembly 5 for installation. Cooling water pipes 1001 are installed inside the moving die plate 201.

[0064] As Figure 4 shown in the figure, the ultrasonic vibration assembly 5 includes: an ultrasonic generator 501, an ultrasonic transducer 502, an ultrasonic horn 503, and an ultrasonic tool head 504. Among them, the ultrasonic transducer 502, the ultrasonic horn 503, and the ultrasonic tool head 504 are coaxially fixedly connected in sequence. The ultrasonic transducer 502 is coaxially fixedly connected to the driving assembly one 7, and the ultrasonic generator 501 is connected to the ultrasonic transducer 502; the front end of the ultrasonic tool head 504 is an equal-diameter cylinder, passing through the through holes 202 on the moving die plate 201 and the moving die base plate 203. The high-frequency excitation voltage generated by the ultrasonic generator 501 is transmitted to the ultrasonic transducer 502. Under the action of the inverse piezoelectric effect, the ultrasonic transducer 502 generates high-frequency vibration. Through the amplification of the ultrasonic horn 503, the ultrasonic tool head 504 generates high-frequency vibration and directly acts on the polymer. The ultrasonic vibration assembly 5 moves axially under the control of the driving assembly one 7.

[0065] As Figure 5 shown in the figure, the driving assembly one 7 includes: a first servo motor 701, a first reducer 702, two first driving wheels 703, a first conveyor belt 704, a first lead screw bearing 705, a first lead screw 706, a first lead screw nut 707, and an ultrasonic tool head push rod 708. The first lead screw bearing 705 is fixedly installed through the through hole provided on the first vertical plate, and the first lead screw bearing 705 is sleeved on the outer circumference of a first driving wheel 703. The first driving wheel 703 is coaxially fixedly connected to the first lead screw 706. A first lead screw nut 707 meshing with it is sleeved on the first lead screw 706. The first lead screw nut 707 is coaxially fixedly connected to the ultrasonic tool head push rod 708, and the ultrasonic tool head push rod 708 is fixedly connected to the ultrasonic transducer 502. The output shaft of the first servo motor 701 is fixedly connected to the input shaft of the first reducer 702, and the output shaft of the first reducer 702 is fixedly connected to the other first driving wheel 703; the two first driving wheels 703 are connected by the first conveyor belt 704 to achieve synchronous rotation. In actual application, the first servo motor 701 and the first reducer 702 drive the first conveyor belt 704 to rotate, thereby driving the first lead screw 706 to rotate. Through the screw meshing effect, the first lead screw nut 707 moves axially, and finally drives the ultrasonic tool head 504 to move axially.

[0066] As Figure 6As shown in the figure, the fixed mold assembly 4 includes: a fixed mold plate 401, a fixed mold base plate 402, a plasticizing cavity 403, a feed inlet 404, a cavity 405, and a circular tube 406. The fixed mold base plate 402 is fixedly connected to the second vertical plate through a support rod, and a control system 11 is installed on the support rod, which is used to receive the data measured by the measuring assembly 9 and control the first driving assembly 7, the second driving assembly 8, and the temperature control assembly 10. The moving mold plate 201, the fixed mold plate 401, the fixed mold base plate 402, and the second vertical plate are arranged in parallel and coaxial in sequence. When the mold is closed, the moving mold plate 201 is attached to the fixed mold plate 401. A cooling water pipe 1001 is installed inside the fixed mold plate 401; a through hole is opened at the central position of the fixed mold plate 401, and its diameter is the same as that of the ultrasonic tool head 504. A cavity 405 is opened on the surface of the fixed mold plate 401 facing the moving mold plate 201 for the final injection molding. The cavity 405 is communicated with the through hole on the fixed mold plate 401, and its size is set according to actual requirements.

[0067] The fixed mold plate 401 and the fixed mold base plate 402 are fixedly connected through a support rod. A circular tube 406 is arranged between the fixed mold plate 401 and the fixed mold base plate 402. One end of the circular tube 406 is inserted into the fixed mold plate 401 and does not penetrate. The circular tube 406 is coaxial and communicated with the through hole on the fixed mold plate 401, and the inner diameter of the circular tube 406 is the same as the diameter of the through hole. The cavity formed by the inside of the circular tube 406 and the through hole on the fixed mold plate 401 is denoted as the plasticizing cavity 403. The feeding assembly 1 is installed between the fixed mold plate 401 and the fixed mold base plate 402; a feed inlet 404 is opened on the upper surface of the end of the circular tube 406 away from the fixed mold plate 401 for communicating the feeding assembly 1 and the plasticizing cavity 403. A through window is opened at the central position of the fixed mold base plate 402 for installing the second driving assembly 8.

[0068] As Figure 7 shown, the feeding assembly 1 includes: a feeding cylinder 101, an electromagnetic ball valve 102, a weighing cylinder 103, a feed valve plate 104, and a precision weighing sensor 105. The feeding cylinder 101 is used to contain polymer materials. The weighing cylinder 103 is tubular and is coaxially installed at the lower end of the feeding cylinder 101 and communicated with it. An electromagnetic ball valve 102 is arranged between the feeding cylinder 101 and the weighing cylinder 103 to control the inflow of polymer materials. A feed valve plate 104 is arranged in the weighing cylinder 103, and a precision weighing sensor 105 is arranged below the feed valve plate 104. The feed valve plate 104 and the precision weighing sensor 105 cooperate with each other. When the feed valve plate 104 is in the closed state, the precision weighing sensor 105 weighs the polymer materials loaded on the feed valve plate 104; when the weight of the polymer materials loaded on the feed valve plate 104 reaches the set value, the feed valve plate 104 opens, and the polymer materials fall due to gravity. The polymer materials after weighing by the feeding assembly 1 enter the plasticizing cavity 403 through the feed inlet 404. In this embodiment, the opening and closing of the feed valve plate 104 are controlled by radially moving the precision weighing sensor 105.

[0069] As shown Figure 8 in the figure, the mechanical vibration assembly 6 includes: a vibration gasket 601, a vibration connecting rod 602, and a voice coil motor 603. The vibration gasket 601 is coaxially and fixedly connected to one end of the vibration connecting rod 602, and the other end of the vibration connecting rod 602 is coaxially and fixedly connected to the output shaft of the voice coil motor 603. The voice coil motor 603 drives the vibration connecting rod 602 and the vibration gasket 601 to perform mechanical vibration. The ultrasonic tool head 504, the vibration gasket 601, and the plasticizing cavity 403 are coaxial, and the diameter of the vibration gasket 601 is the same as the inner diameter of the plasticizing cavity 403. The initial position of the vibration gasket 601 is located at one end of the plasticizing cavity 403 close to the fixed mold base plate 402.

[0070] As shown Figure 9 in the figure, the driving assembly two 8 includes: a second servo motor 801, a second reducer 802, two second driving wheels 803, a second conveyor belt 804, a second lead screw bearing 805, a second lead screw nut 806, a second lead screw 807, a slider 808, a slide rail 809, a support plate 810, and a voice coil motor push rod 811. The bottom of the voice coil motor 603 is fixedly connected to the slider 808. The slider 808 is installed on the slide rail 809, and the slide rail 809 is fixedly connected to the support plate 810. One end of the support plate 810 is fixedly connected to the second vertical plate of the bracket 12, and the other end is installed in and fixedly connected to a window opened at the center position of the fixed mold base plate 402. The second lead screw bearing 805 is fixedly installed through a through hole opened on the second vertical plate, and the second lead screw bearing 805 is sleeved on the outer circumference of a second driving wheel 803. The second driving wheel 803 is coaxially and fixedly connected to the second lead screw 807. A second lead screw nut 806 meshing with the second lead screw 807 is sleeved on the second lead screw 807. The second lead screw nut 806 is fixedly connected to the voice coil motor push rod 811, and the voice coil motor push rod 811 is fixedly connected to the voice coil motor 603. The output shaft of the second servo motor 801 is fixedly connected to the input shaft of the second reducer 802, and the output shaft of the second reducer 802 is fixedly connected to the other second driving wheel 803. The two second driving wheels 803 are connected by the second conveyor belt 804 to achieve synchronous rotation. In actual application, the second servo motor 801 and the second reducer 802 drive the second driving wheel 803 to rotate, thereby driving the second conveyor belt 804 and the second lead screw 807 to rotate. Through the thread meshing effect, the second lead screw nut 806 performs axial movement, thereby pushing the mechanical vibration assembly 6 to perform axial movement, and finally realizing the axial movement of driving the vibration gasket 601.

[0071] As shown Figure 10As shown in the figure, the ultrasonic plasticizing micro-injection molding device based on the composite dynamic force field further includes a measurement component 9, and the measurement component 9 includes a temperature sensor 901 and a pressure sensor 902. There are two temperature sensors 901, which are respectively arranged at the inlet and outlet positions of the plasticizing cavity 403 for detecting the temperature in the plasticizing cavity 403; there are two pressure sensors 902, which are also respectively arranged at the inlet and outlet positions of the plasticizing cavity 403 for detecting the pressure inside the plasticizing cavity 403. The heating coil 1002 is arranged around the sensor corresponding to the measurement component 9 on the outer circumference of the circular tube 406 corresponding to the plasticizing cavity 403.

[0072] As Figure 11 and Figure 12 shown in the figure, based on the above ultrasonic plasticizing micro-injection molding device based on the composite dynamic force field, an ultrasonic plasticizing micro-injection molding method based on the composite dynamic force field is proposed, which specifically includes the following steps:

[0073] Step 1: Mold clamping stage. The moving mold hydraulic component 3 drives the moving mold component 2 to move axially, so that the moving template 201 is closely attached to the fixed template 401 to complete the mold clamping action. At the same time, the driving component 1 7 drives the ultrasonic tool head 504 to move axially, so that during the mold clamping process, the position of the ultrasonic tool head 504 remains relatively stationary with respect to the moving mold component 2, thereby reducing the friction loss of the ultrasonic tool head 504 and prolonging the service life of the ultrasonic tool head 504. When the moving mold component 2 and the fixed mold component 4 complete the mold clamping action, the moving mold hydraulic component 3 stops working. At this time, the end face of the ultrasonic tool head 504 is located at one end of the plasticizing cavity 403.

[0074] Step 2: Feeding stage. In the initial state, the electromagnetic ball valve 102 is in the closed state, the feeding valve piece 104 is in the closed state, and the precision weighing sensor 105 is located below the feeding valve piece 104. When starting to feed, first open the electromagnetic ball valve 102 to make the polymer material enter the weighing cylinder 103 from the feeding cylinder 101. At this time, since the feeding valve piece 104 is closed, the polymer material falls on the feeding valve piece 104, and the weight of the polymer material entering is measured by the precision weighing sensor 105. When the weight of the polymer material reaches the plasticizing requirement, close the electromagnetic ball valve 102, move the precision weighing sensor 105 radially to make the feeding valve piece 104 in the open state, and the polymer material flows into the plasticizing cavity 403 through the feeding port 404 due to gravity. When the polymer material completely enters the plasticizing cavity 403, move the precision weighing sensor 105 radially again to make the feeding valve piece 104 return to the closed state. At this time, the driving component 1 7 drives the ultrasonic tool head 504 to perform a small amplitude axial movement, and finally makes the ultrasonic tool head 504 enter the plasticizing cavity 403 and isolate the plasticizing cavity 403 from the cavity 405.

[0075] Step 3: Plasticization preparation stage. After the polymer material enters the plasticization cavity 403, the second driving component 8 drives the mechanical vibration component 6 to move axially, initially compressing the polymer material by the vibration gasket 601 and isolating the plasticization cavity 403 from the feeding channel. At this time, a closed space is formed in the plasticization cavity 403. The heating coil 1002 starts to preheat the plasticization cavity 403.

[0076] Step 4: Plasticization process stage. The high-frequency excitation voltage emitted by the ultrasonic generator 501 is transmitted to the ultrasonic transducer 502. Under the action of the inverse piezoelectric effect, the ultrasonic transducer 502 generates high-frequency vibrations. Through the amplification of the ultrasonic horn 503, the ultrasonic tool head 504 generates high-frequency and low-amplitude vibrations and directly acts on the polymer material in the plasticization cavity 403. At the same time, the voice coil motor 603 starts to operate, applying low-frequency and high-amplitude vibrations to the polymer material in the plasticization cavity 403 through the vibration gasket 601, so as to form a dynamic force field composed of the composite of ultrasonic vibration and mechanical vibration in the plasticization cavity 403. Due to the frictional heat effect and the poor heat transfer performance of the polymer, a layer of polymer near the ultrasonic tool head 504 is quickly plasticized. At this time, under the action of the vibration gasket 601, the unplasticized polymer particles are mixed with the melt, and some unplasticized particles are pushed near the ultrasonic tool head 504 under the action of mechanical vibration and rub violently with the ultrasonic tool head 504 to start generating heat rapidly. At the same time, under the action of the viscoelastic effect and the ultrasonic cavitation effect, the polymer particles are continuously plasticized to form a polymer melt.

[0077] With the continuous progress of ultrasonic plasticization, the pressure loss between polymer particles gradually decreases, and the pressure value detected by the pressure sensor 902 slowly increases. Finally, when the polymer material in the plasticization cavity 403 is completely melted, the measured pressure value is the largest. Therefore, when the pressure value in the plasticization cavity 403 measured by the pressure sensor 902 reaches the maximum, it is determined that the polymer material is completely plasticized.

[0078] Step 5: Injection stage. When the polymer is completely plasticized, the voice coil motor 603 and the ultrasonic tool head 504 continue to work to maintain the application of the composite dynamic force field; and the first driving component 7 is activated to make the ultrasonic tool head 504 move axially in a small amplitude away from the plasticization cavity 403, connecting the plasticization cavity 403 with the cavity 405. Then, the second driving component 8 drives the voice coil motor 603 to move in a uniform straight line along the slide rail 809. Since the voice coil motor 603 still applies periodic mechanical vibrations at this time, the vibration gasket 601 performs periodic movements, and the speed curve is as Figure 13 shown, introducing a pulsating force field into the injection process. The pulsating force field applied by the vibration gasket 601 injects the polymer melt into the cavity 405.

[0079] Step 6: Pressure holding stage. After the polymer melt completely fills the cavity 405, the second driving component 8 stops operating. At this time, the vibration gasket 601 and the ultrasonic tool head 504 continue to vibrate for pressure holding. The pressure holding should ensure that the polymer melt is fully filled in the cavity and avoid surface defects of the product. The pressure holding time can be appropriately adjusted according to the material fluidity and the mold structure.

[0080] Step 7: Cooling and forming stage. The heating coil 1002 stops heating, and the ultrasonic vibration component 5 and the voice coil motor 603 stop working. Cooling water is introduced into the cooling water pipe 1001 to take away heat, and the temperature of the polymer melt drops rapidly and cools and forms.

[0081] Step 8: Mold opening stage. The moving mold hydraulic component 3 drives the moving mold component 2 to move axially away from the fixed template 401. At the same time, the first driving component 7 drives the ultrasonic tool head 504 to perform an axial movement so that it remains relatively stationary with the moving mold component 2.

[0082] Step 9: Ejection stage. The second driving component 8 starts to operate, pushing the vibration gasket 601 to perform an axial linear movement, so that the vibration gasket 601 ejects the formed micro product. After the ejection is completed, the second driving component 8 drives the vibration gasket 601 back to the initial position before mold closing.

[0083] The present invention introduces a dynamic force field formed by compounding ultrasonic vibration and mechanical vibration into the whole process of injection molding (plasticization, injection, and pressure holding stages). Compared with traditional micro-injection devices using screws or pistons, the device of the present invention has a simple structure, lower energy consumption, a lower waste rate of raw materials, and higher dimensional accuracy. Compared with existing ultrasonic plasticization micro-injection devices, for the plasticization process, the present invention has higher plasticization efficiency and more uniform and stable plasticization; for the injection process, the present invention adds a pulsating pressure on the basis of the ultrasonic cavitation effect, causing the melt to undergo volume tensile deformation. Under the action of the pulsating force field, the polymer chains will undergo behaviors such as disentanglement, orientation, and stretching, further reducing the material viscosity and inducing the formation of an oriented structure, thereby further reducing the molding pressure, shortening the filling time, and reducing molding defects; for the pressure holding process, the introduction of the compound dynamic force field increases the cavity pressure, extends the closing time of the gate, and greatly improves the filling quality and dimensional accuracy of micro-nano products.

[0084] At the same time, through the control of the moving mold hydraulic component 3 and the first driving component 7, the ultrasonic tool head 504 only performs a small-amplitude axial movement in the initial stage of injection, realizing the decoupling of the plasticization stage and the injection stage, and extending the service life of the ultrasonic tool head 504. Through the combination of the mechanical vibration component 6 and the second driving component 8, a pulsating pressure is added during the injection process. Since the present invention does not require the driving screw to rotate, compared with the existing volume pulsating injection molding technology, it has a simple structure, low cost, and convenient control.

[0085] Those of ordinary skill in the art can understand that the above are only preferred examples of the invention and are not used to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, etc. made within the spirit and principles of the invention shall be included within the protection scope of the invention.

Claims

1. An ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field, characterized in that, Including: A feeding component, a moving mold component, a moving mold hydraulic component, a fixed mold component, an ultrasonic vibration component, a mechanical vibration component, a driving component I, a driving component II, a measuring component, a temperature control component, a control system, and a bracket; the control system receives data from the measuring component and controls the feeding component, the moving mold hydraulic component, the ultrasonic vibration component, the mechanical vibration component, the two driving components, and the temperature control component. The bracket includes a first vertical plate and a second vertical plate arranged parallel and opposite to each other. The fixed end of the moving mold hydraulic component is fixedly connected to the first vertical plate, and its moving end is fixedly connected to the moving mold component to control the axial movement of the moving mold component; the driving component I is fixedly connected to the first vertical plate, and an ultrasonic vibration component is fixedly connected thereto and drives the ultrasonic vibration component to perform axial movement; the ultrasonic tool head of the ultrasonic vibration component is coaxial with the moving mold component and passes through the moving mold component; the moving mold component is parallel to the first vertical plate. The fixed mold component includes a fixed mold plate and a fixed mold base plate arranged parallel and coaxial. The fixed mold base plate is fixedly connected to the second vertical plate in parallel; one end of the driving component II is fixedly connected to the second vertical plate, and the other end passes through a window in the center of the fixed mold base plate and is fixedly connected; a mechanical vibration component is fixedly connected to the driving component II and drives the mechanical vibration component to perform axial movement; the moving mold component is closely attached to the fixed mold plate during mold closing. A through hole with the same diameter as the ultrasonic tool head is opened at the center of the fixed mold plate. A cavity communicating with the through hole is provided on the surface of the fixed mold plate facing the moving mold component. A circular tube with the same inner diameter as the through hole is inserted at the center of the surface facing the fixed mold base plate, and the circular tube is coaxial and communicates with the through hole. The formed cylindrical cavity is a plasticizing cavity; a feed port is opened on the circular tube for communicating the feeding component and the plasticizing cavity, and the feeding component is used for quantitatively conveying polymer materials. The ultrasonic tool head, the vibration shim of the mechanical vibration component, and the plasticizing cavity are coaxial, and the diameter of the vibration shim is the same as that of the plasticizing cavity; the ultrasonic tool head is used to generate high-frequency and low-amplitude vibrations, and the mechanical vibration component is used to generate low-frequency and high-amplitude vibrations. The temperature control component includes a cooling water pipe and a heating coil. The cooling water pipe is arranged inside the moving mold component and inside the fixed mold plate, and the heating coil is arranged on the outer periphery of the circular tube; the measuring component is used to measure the temperature and pressure inside the plasticizing cavity.

2. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, wherein The ultrasonic vibration component includes: an ultrasonic generator, an ultrasonic transducer, an ultrasonic horn, and an ultrasonic tool head; the ultrasonic transducer, the ultrasonic horn, and the ultrasonic tool head are coaxially and fixedly connected in sequence. The ultrasonic transducer is coaxially and fixedly connected to the driving component I, and the ultrasonic generator is connected to the ultrasonic transducer; the ultrasonic generator is used to generate a high-frequency excitation voltage. The ultrasonic transducer receives the high-frequency excitation voltage and generates high-frequency vibrations. The ultrasonic horn is used to amplify the vibrations and transmit them to the ultrasonic tool head.

3. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, wherein, The mechanical vibration component includes: a vibration shim, a vibration connecting rod, and a voice coil motor; the vibration shim is coaxially and fixedly connected to one end of the vibration connecting rod, and the other end of the vibration connecting rod is coaxially and fixedly connected to the output shaft of the voice coil motor. The voice coil motor drives the vibration connecting rod and the vibration shim to perform mechanical vibrations.

4. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, wherein, The feeding assembly includes: a feeding cylinder, an electromagnetic ball valve, a weighing cylinder, a feeding valve plate, and a precision weighing sensor; the feeding cylinder is used to contain polymer materials, the weighing cylinder is tubular, coaxially installed at the lower end of the feeding cylinder and communicated with it; an electromagnetic ball valve is arranged between the feeding cylinder and the weighing cylinder to control the inflow of polymer materials; a feeding valve plate is arranged in the weighing cylinder, and a precision weighing sensor is arranged below the feeding valve plate; when the feeding valve plate is in the closed state, the precision weighing sensor weighs the weight of the polymer materials loaded on the feeding valve plate; when the weight of the polymer materials loaded on the feeding valve plate reaches the set value, the feeding valve plate opens, and the polymer materials fall due to gravity, and the polymer materials after being metered and weighed by the feeding assembly enter the plasticizing cavity through the feeding port.

5. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, wherein, The moving die hydraulic assembly includes: a hydraulic rod, a hydraulic actuator, and a hydraulic power unit; the hydraulic actuator and the hydraulic power unit are respectively fixedly connected to the first vertical plate, and the hydraulic power unit is connected to the hydraulic actuator to provide power for it; the hydraulic rod is coaxially installed in the hydraulic actuator to achieve telescoping, and the top of the hydraulic rod is fixedly connected to the moving die assembly.

6. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, characterized in that, The moving die assembly includes a moving die plate and a moving die base plate arranged in parallel and coaxially. One side of the moving die base plate is fixedly connected to the moving die hydraulic assembly, and the other side is fixedly connected to the moving die plate, and the moving die base plate is parallel to the first vertical plate; the moving die plate and the fixed die plate are closely attached when the mold is closed; mounting holes are opened at the centers of the moving die plate and the moving die base plate for installing the ultrasonic tool head; cooling water pipes are arranged inside the moving die plate.

7. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, characterized in that, The first driving assembly includes: a first servo motor, a first reducer, two first driving wheels, a first conveyor belt, a first lead screw bearing, a first lead screw, a first lead screw nut, and an ultrasonic tool head push rod; the first lead screw bearing is fixedly installed through the through hole opened on the first vertical plate, and the first lead screw bearing is sleeved on the outer circumference of a first driving wheel; the first driving wheel is coaxially fixedly connected to the first lead screw, a first lead screw nut meshing with the first lead screw is sleeved on the first lead screw, the first lead screw nut is coaxially fixedly connected to the ultrasonic tool head push rod, and the ultrasonic tool head push rod is fixedly connected to the ultrasonic vibration assembly; the output shaft of the first servo motor is fixedly connected to the input shaft of the first reducer, and the output shaft of the first reducer is fixedly connected to the other first driving wheel; the two first driving wheels are connected by a first conveyor belt to achieve synchronous rotation.

8. The ultrasonic plasticizing micro-injection molding device based on a composite dynamic force field according to claim 1, wherein, The second driving assembly includes: a second servo motor, a second reducer, two second driving wheels, a second conveyor belt, a second lead screw bearing, a second lead screw nut, a second lead screw, a slider, a slide rail, a support plate, and a voice coil motor push rod; one end of the support plate is fixedly connected to the second vertical plate of the bracket, and the other end is installed on and fixedly connected to the window opened at the center position of the fixed die base plate; a slide rail is fixedly connected to the support plate, a slider is installed on the slide rail, and the upper surface of the slider is fixedly connected to the mechanical vibration assembly; The second lead screw bearing is fixedly installed through a through hole formed in the second vertical plate. The second lead screw bearing is sleeved on the outer periphery of a second transmission wheel. The second transmission wheel is coaxially and fixedly connected to the second lead screw. A second lead screw nut meshing with the second lead screw is sleeved on the second lead screw. The second lead screw nut is fixedly connected to the voice coil motor push rod. The voice coil motor push rod is fixedly connected to the mechanical vibration assembly. The output shaft of the second servo motor is fixedly connected to the input shaft of the second reducer. The output shaft of the second reducer is fixedly connected to another second transmission wheel. The two second transmission wheels are connected by a second conveyor belt to achieve synchronous rotation.

9. An ultrasonic plasticizing micro-injection molding method based on a composite dynamic force field, which is realized by the ultrasonic plasticizing micro-injection molding device according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1, mold closing stage: The moving mold hydraulic assembly drives the moving mold assembly to move axially, so that the moving mold assembly is closely attached to the fixed template to complete the mold closing action. At the same time, the driving assembly 1 drives the ultrasonic tool head to move axially, so that during the mold closing process, the position of the ultrasonic tool head and the moving mold assembly remains relatively stationary. After the mold closing action is completed, the moving mold hydraulic assembly stops working. At this time, the end face of the ultrasonic tool head is located at one end of the plasticizing cavity. Step 2, feeding stage: The polymer material after being metered and weighed by the feeding assembly enters the plasticizing cavity from the feeding port. When the polymer material completely enters the plasticizing cavity, the feeding assembly stops working. At the same time, the driving assembly 1 drives the ultrasonic tool head into the plasticizing cavity and isolates the plasticizing cavity from the mold cavity. Step 3, plasticizing preparation stage: The driving assembly 2 pushes the mechanical vibration assembly to move axially, so that the vibration gasket initially compresses the polymer material and isolates the plasticizing cavity from the feeding port. At this time, a closed space is formed in the plasticizing cavity. The heating coil starts to preheat the plasticizing cavity. Step 4, plasticizing process stage: The ultrasonic vibration assembly starts to work. The ultrasonic tool head generates high-frequency and low-amplitude vibrations and directly acts on the polymer material in the plasticizing cavity. At the same time, the mechanical vibration assembly starts to operate, and applies low-frequency and high-amplitude vibrations to the polymer material in the plasticizing cavity through the vibration gasket, so as to form a dynamic force field composed of ultrasonic vibration and mechanical vibration in the plasticizing cavity. The polymer particles are continuously plasticized to form polymer melt. As the ultrasonic plasticizing continues, the pressure loss between the polymer particles gradually decreases, and the pressure value in the plasticizing cavity slowly increases. When the pressure value in the plasticizing cavity reaches the maximum, it is determined that the polymer material is completely plasticized. Step 5, injection stage: When the polymer is completely plasticized, the ultrasonic vibration assembly and the mechanical vibration assembly continue to work to maintain the applied composite dynamic force field. And the driving assembly 1 is turned on to make the ultrasonic tool head move axially away from the plasticizing cavity, so that the plasticizing cavity is connected to the mold cavity. The driving assembly 2 drives the mechanical vibration assembly to move axially towards the mold cavity to inject the polymer melt into the mold cavity. Step 6, pressure holding stage: When the polymer melt is completely filled into the mold cavity, the driving assembly 2 stops running. The ultrasonic vibration assembly and the mechanical vibration assembly continue to work for a period of time to hold the pressure, so that the polymer melt is fully filled in the mold cavity and avoid surface defects of the product. Step 7, cooling and forming stage: The heating coil stops heating, and the ultrasonic vibration assembly and the mechanical vibration assembly stop working. Cooling water is introduced into the cooling water pipe to lower the temperature of the polymer melt and cool it into shape. Step 8. Mold opening stage: The moving mold hydraulic component drives the moving mold component to move axially away from the fixed mold plate. At the same time, the driving component 1 drives the ultrasonic tool head to move axially so that it remains relatively stationary with respect to the moving mold component. Step 9. Ejection stage: The driving component 2 starts to operate, pushing the vibration gasket to move axially to eject the molded micro product. After the ejection is completed, the driving component 2 drives the vibration gasket back to the initial position before the mold closing starts.

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