Silica gel production equipment for communication chip packaging and working method thereof

Abstract

The invention relates to silica gel production equipment for communication chip packaging and a working method thereof.The silica gel production equipment comprises a stirring barrel, a feeding opening is formed in the stirring barrel, a discharging valve is installed at the bottom of the stirring barrel, the top of the stirring barrel is connected with a vacuum pump through a vacuum pipe, and a gearbox is installed on the top side of the stirring barrel; a rotating disc is rotatably mounted on the bottom side of the gearbox, a main stirring shaft is mounted at the center of the rotating disc in a penetrating manner, auxiliary stirring shafts are rotatably mounted on the periphery of the rotating disc, and a second inner gear ring is rotatably mounted on the inner side of the stirring barrel. The main stirring shaft drives the rotating disc to revolve, the auxiliary stirring shaft rotates through gear meshing while revolving, a revolution-rotation composite motion track is formed, stirring dead angles are eliminated, raw materials such as A / B component silica gel, color paste and a catalyst are fully sheared, convected and diffused in a three-dimensional space, the mixing uniformity can reach 98% or above, and the mixing uniformity far exceeds that of a traditional single stirring mode.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging material production equipment technology, and in particular to a silicone production equipment for communication chip packaging and its working method. Background Technology

[0002] The packaging of communication chips requires extremely high standards for the uniformity, purity, bubble content, and curing performance of silicone.

[0003] Traditional silicone production equipment often employs simple stirring or static degassing methods, resulting in uneven mixing, incomplete degassing, and low production efficiency. In particular, trace amounts of moisture and air bubbles in the silicone are difficult to remove, affecting the electrical performance and reliability of the encapsulated product. While microwave treatment can efficiently heat and dehumidify, traditional microwave equipment struggles to achieve uniform irradiation during the stirring process. Summary of the Invention

[0004] The problem solved by this invention is to provide a silicone production equipment and its working method for communication chip packaging, which realizes efficient stirring, degassing and microwave uniform treatment of silicone in a vacuum environment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A silicone production device for communication chip packaging includes a mixing drum with a feed inlet and a discharge valve at the bottom. The top of the mixing drum is connected to a vacuum pump via a vacuum tube. A gearbox is mounted on the top side of the mixing drum, and a turntable is rotatably mounted on the bottom side of the gearbox. A main stirring shaft is installed through the center of the turntable, and auxiliary stirring shafts are rotatably mounted around the turntable. A second internal gear ring is rotatably mounted inside the mixing drum, and support arms are symmetrically mounted on the bottom side of the second internal gear ring. Several microwave transmitters are mounted at equal intervals on the support arms.

[0006] Preferably, a sealing cover is detachably installed on the feed inlet, and a vacuum pressure gauge is installed on the mixing drum.

[0007] Preferably, the main stirring shaft is fixedly connected to the turntable, and a first motor is installed on the gearbox, with the output end of the first motor connected to the main stirring shaft.

[0008] Preferably, the gearbox is provided with a first internal gear ring, the auxiliary stirring shaft is connected to the turntable through a bearing, the auxiliary stirring shaft is equipped with rotating teeth, and the rotating teeth mesh with the first internal gear ring.

[0009] Preferably, the second internal toothed ring is connected to the stirring cylinder bearing, the stirring cylinder is equipped with a second motor, the output end of the second motor is equipped with a drive tooth, and the drive tooth meshes with the second internal toothed ring.

[0010] Preferably, the inner wall of the stirring drum is coated with polytetrafluoroethylene, and the outer wall of the stirring drum is provided with a jacket, through which heat transfer oil or cooling water is circulated.

[0011] Preferably, the microwave transmitter operates at a frequency of 2450MHz and has an adjustable power range of 0-2000W.

[0012] Preferably, both the main stirring shaft and the auxiliary stirring shaft are provided with stirring blades, and the stirring blades on the main stirring shaft and the auxiliary stirring shaft are arranged alternately.

[0013] A working method of a silicone production equipment for communication chip packaging, S1. Open the detachable sealing cover of the feed port, and sequentially add raw materials such as component A silicone, component B silicone, color paste, and catalyst. Close the sealing cover and lock the sealing structure to form a closed cavity inside the mixing drum. S2. Start the first motor and drive the main stirring shaft to rotate at a low speed of 50–100 rpm, which will drive the turntable to revolve and the auxiliary stirring shaft to rotate synchronously to carry out preliminary mixing for 3–5 minutes to allow the components to be initially dispersed. S3. Start the vacuum pump and evacuate the inside of the stirring tank through the vacuum tube until the vacuum pressure gauge shows a pressure ≤ -0.095 MPa, and maintain this vacuum level; S4. Increase the speed of the first motor to 300–600 rpm to enter the high-speed compound stirring stage. Under high vacuum, the bubbles inside the material expand rapidly due to the reduction of external pressure. At the same time, affected by the shear force and lifting effect of the stirring blades, the bubbles break and float out along the stirring flow line. The degassing process lasts for 10–20 minutes. S5. Start the second motor and drive the active gear to rotate at a speed of 5–15 rpm, which will drive the microwave transmitter on the second internal gear ring and the support arm to rotate at a constant speed. At the same time, turn on the microwave transmitter, set the output power to 800–1500 W, and the irradiation time to 8–15 minutes. The microwave energy penetrates the material layer evenly, causing the water molecules to polarize, generate heat, and evaporate. S6. The jacket temperature control system automatically adjusts the temperature of the heat transfer oil based on the feedback signal from the temperature sensor installed on the inner wall of the mixing drum, so that the material temperature is maintained within the process setting range of 40–60℃, preventing excessive local temperature caused by microwave heating from triggering silicone pre-crosslinking or aging. S7. After microwave treatment, turn off the microwave transmitter and the second motor, but continue to keep the first motor running and the vacuum pump running for 10–15 minutes to further homogenize the material under vacuum and stirring conditions and eliminate viscosity differences. S8. The jacket is switched to cooling water circulation mode, the cooling water temperature is controlled at 15–25℃, the circulation time is 8–12 minutes, and the material temperature is reduced to below 30℃. S9. Turn off the vacuum pump and introduce clean nitrogen into the mixing drum through the air inlet valve to restore the internal pressure to normal pressure. Then open the discharge valve and at the same time, the first motor runs at a low speed of 30-50 rpm to help the material be discharged smoothly and avoid eddies or secondary air entrainment during the discharge process. The main and auxiliary stirring shafts feature helical blades with an upward spiral angle. The helical direction of the main stirring blades is opposite to that of the auxiliary stirring blades, creating a counter-shear flow field. There are 3–6 auxiliary stirring shafts, evenly distributed along the circumference of the turntable, with their rotation direction opposite to their revolution direction, enhancing the material tumbling effect. There are 4–8 microwave emitters, equidistantly arranged along the length of the support arm, with an axial spacing of 50–100 mm between adjacent emitters, ensuring uniform microwave irradiation of the material layer in the height direction. The vacuum pump is a two-stage rotary vane vacuum pump with an ultimate vacuum of -0.098 MPa and a pumping rate of no less than 120 L / min, meeting the requirement for rapidly establishing a high vacuum environment. The discharge valve is a pneumatic ball valve or an electric butterfly valve, with quick opening and closing functions, controlling the discharge time to within 30 seconds, reducing material exposure time.

[0014] The beneficial effects of this invention are: The main stirring shaft drives the turntable to revolve, while the auxiliary stirring shaft rotates on its own axis through gear meshing, forming a "revolution-rotation" composite motion trajectory. This eliminates dead zones in the mixing process, allowing raw materials such as silica gel, color paste, and catalyst in components A and B to undergo full shearing, convection, and diffusion in three-dimensional space. The mixing uniformity can reach over 98%, far exceeding that of traditional single stirring methods. The vacuum pump maintains the vacuum level inside the mixing drum below -0.095MPa. During the mixing process, bubbles expand and burst rapidly. Combined with the upward action of the spiral stirring blades, the escape path of the bubbles is short and the resistance is low. The wave emitter rotates with the second inner toothed ring, and microwave energy evenly irradiates the entire material layer. Moisture molecules are polarized and generate heat in the high-frequency electric field, achieving rapid low-temperature dehumidification and avoiding local overheating that could lead to silica gel aging. The moisture content can be controlled below 50ppm. The microwaves act directly on the material molecules, with a thermal efficiency of over 85%. The heating rate is 3-5 times higher than that of traditional heat conduction methods, and the stirring motion prevents heat accumulation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is an overall side view of the invention; Figure 3 This is a schematic diagram of the first internal structure of the present invention; Figure 4 This is a schematic diagram of the second internal structure of the present invention; Figure 5 This is a schematic diagram of the internal structure of the gearbox of the present invention.

[0016] Legend: 1. Mixing drum; 2. Feed inlet; 3. Discharge valve; 4. Vacuum tube; 5. Vacuum pump; 6. Gearbox; 7. Turntable; 8. Main mixing shaft; 9. Auxiliary mixing shaft; 10. First motor; 11. First internal gear ring; 12. Rotary gear; 13. Second internal gear ring; 14. Support arm; 15. Microwave transmitter; 16. Second motor; 17. Drive gear. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Specific implementation examples are given below.

[0019] See Figures 1 to 5 As shown, the present invention provides a silicone production equipment and its working method for communication chip packaging. In actual operation, through the coordinated cooperation of various structural components, it achieves highly uniform mixing, efficient degassing, and low-temperature deep dehumidification of multiphase materials such as A / B component silicone, color paste, and catalyst. The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. like Figure 1 and Figure 2 As shown, the main body of the equipment is a mixing drum 1, with a feed inlet 2 at the top, a discharge valve 3 at the bottom, and a vacuum pump 5 connected to the top via a vacuum tube 4. A sealing cover is detachably installed on the feed inlet 2 to ensure a sealed operating space is formed after feeding. A vacuum pressure gauge is installed on the outer wall of the mixing drum 1 to monitor the internal vacuum level in real time. A gearbox 6 is fixedly installed on the top side of the mixing drum 1, and a turntable 7 is rotatably mounted on the bottom side of the gearbox 6 via bearings. A main stirring shaft 8 is installed through the center of the turntable 7, and four auxiliary stirring shafts 9 are evenly distributed around its perimeter. The main stirring shaft 8 is fixedly connected to the turntable 7 and is driven to rotate by a first motor 10 mounted on the gearbox 6. Figure 5 As shown, a first internal gear ring 11 is fixedly installed inside the gearbox 6, and a rotating tooth 12 is installed on the upper end of the auxiliary stirring shaft 9. The rotating tooth 12 meshes with the first internal gear ring 11. When the first motor 10 is started, the main stirring shaft 8 drives the turntable 7 to revolve around the central axis of the stirring drum 1. While the auxiliary stirring shaft 9 revolves with the turntable 7, it rotates in the opposite direction due to the meshing of the rotating tooth 12 with the fixed first internal gear ring 11, forming a "revolution-rotation" composite motion trajectory. Both the main stirring shaft 8 and the auxiliary stirring shaft 9 are equipped with helical angle stirring blades, and the main and auxiliary stirring blades are staggered in the axial and radial directions, so that the material undergoes multiple actions of shearing, convection and diffusion in three-dimensional space. like Figure 3 and Figure 4 As shown, a second internal gear ring 13 is rotatably mounted on the inner side of the stirring drum 1 via bearings. Two support arms 14 are symmetrically arranged on its bottom side, and six microwave transmitters 15 are evenly spaced on each support arm 14, with an axial distance of 80 mm between adjacent microwave transmitters 15. A second motor 16 is located on the outer wall of the stirring drum 1, and a drive gear 17 is mounted on its output end, meshing with the second internal gear ring 13. When the second motor 16 starts, it drives the second internal gear ring 13 to slowly rotate around the central axis of the stirring drum 1 at a speed of 10 rpm via the drive gear 17, thereby causing the microwave transmitters 15 to revolve uniformly around the material. The microwave transmitter 15 operates at a frequency of 2450 MHz, and its output power can be continuously adjusted within the range of 0–2000 W, with a typical operating power setting of 1200 W. W; Microwave energy penetrates the material layer and selectively acts on polar molecules such as water, causing them to undergo dipole polarization and generate heat through friction in a high-frequency alternating electric field, thereby achieving overall low-temperature heating and water evaporation of the material; As the microwave transmitter 15 rotates with the second inner toothed ring 13, its irradiation direction and intensity change periodically in the circumferential direction, avoiding local energy concentration and ensuring that the microwave energy density received by each area of ​​the material layer is consistent. The inner wall of the mixing drum 1 is coated with a 50 μm thick polytetrafluoroethylene (PTFE) coating. This coating has low surface energy and strong chemical inertness, exhibiting excellent anti-adhesion properties against silicone systems. This effectively prevents materials from adhering to the drum wall during mixing, reducing residue and avoiding cross-contamination between different batches. The outer wall of the mixing drum 1 is equipped with a jacket, forming a closed flow channel inside the jacket, through which heat transfer oil or cooling water can be introduced. The jacket inlet and outlet are respectively connected to an external temperature control system, which includes a temperature sensor, a proportional regulating valve, and a circulating pump. This system automatically adjusts the medium flow rate and temperature according to the set process parameters. During the microwave heating stage, 45°C low-temperature heat transfer oil is introduced into the jacket to absorb heat from local overheated areas and eliminate temperature gradients. During the cooling stage, the system switches to 20°C cooling water circulation to reduce the material temperature to the required discharge range. The jacket temperature control system works in conjunction with the microwave transmitter 15 to maintain the overall material temperature fluctuation within ±2°C. The working method of this invention specifically includes the following steps: S1. Open the detachable sealing cover of the feed port 2, and sequentially add raw materials such as component A silica gel, component B silica gel, color paste, and catalyst. Close the sealing cover and lock the sealing structure to form a sealed cavity inside the stirring drum 1; S2. Start the first motor 10 and drive the main stirring shaft 8 to rotate at a low speed of 80 rpm, driving the turntable 7 to revolve and the auxiliary stirring shaft 9 to rotate synchronously, to perform preliminary mixing for 4 minutes, so that the components are initially dispersed; S3. Start the vacuum pump 5 and evacuate the inside of the stirring drum 1 through the vacuum tube 4 until the vacuum pressure gauge shows a pressure of -0.096 MPa, and maintain this vacuum level; S4. Increase the speed of the first motor 10 to 450 rpm to enter the high-speed compound stirring stage. Under high vacuum, the bubbles inside the material expand rapidly due to the decrease in external pressure. At the same time, affected by the shear force and upward action of the stirring blades, the bubbles burst and float out along the stirring flow line. The degassing process lasts for 15 minutes; S5. The second motor 16 is started, driving the active gear 17 to rotate at a speed of 10 rpm, which in turn drives the microwave transmitter 15 on the second internal gear ring 13 and support arm 14 to revolve at a uniform speed. At the same time, the microwave transmitter 15 is turned on, with the output power set to 1200 W and the irradiation time set to 12 minutes. The microwave energy penetrates the material layer evenly, causing the water molecules to polarize, generate heat, and evaporate. S6. The jacket temperature control system automatically adjusts the temperature of the heat transfer oil according to the feedback signal from the temperature sensor installed on the inner wall of the stirring drum 1, so that the material temperature is maintained within the process setting range of 50°C, preventing the local temperature from becoming too high due to microwave heating, which could cause silicone pre-crosslinking or aging. S7. After the microwave treatment is completed, the microwave transmitter 15 and the second motor 16 are turned off, but the first motor 10 and the vacuum pump 5 continue to operate for 12 minutes to further homogenize the material under vacuum and stirring conditions, eliminating viscosity differences. S8. The jacket is switched to cooling water circulation mode, with the cooling water temperature controlled at 20°C and the circulation time set to 10 minutes, reducing the material temperature to 28°C. S9. Turn off vacuum pump 5 and introduce clean nitrogen into mixing tank 1 through air inlet valve to restore internal pressure to normal pressure. Then open discharge valve 3 and at the same time, first motor 10 runs at low speed of 40 rpm to assist the material to be discharged smoothly and avoid eddies or secondary air entrainment during the discharge process. During the above operation, the stirring blades of the main stirring shaft 8 and the auxiliary stirring shaft 9 adopt a spiral angle design. The spiral direction of the main stirring blade is right-handed, and the spiral direction of the auxiliary stirring blade is left-handed, forming a counter-shear flow field. There are four auxiliary stirring shafts 9, which are distributed at equal angles along the circumference of the turntable 7. Their rotation direction is opposite to their revolution direction, which enhances the material tumbling effect. There are twelve microwave emitters 15, which are arranged at equal intervals along the length of the two support arms 14 to ensure that the material layer also receives uniform microwave irradiation in the height direction. The vacuum pump 5 is a two-stage rotary vane vacuum pump with an ultimate vacuum degree of -0.098 MPa and a pumping rate of not less than 120 L / min, which meets the requirements for quickly establishing a high vacuum environment. The discharge valve 3 is a pneumatic ball valve with a quick opening and closing function, and the discharge time is controlled within 25 seconds to reduce the material exposure time. The gearbox 6 is equipped with a lubrication system, including an oil sump, oil pump, and nozzles, which provides forced lubrication to the meshing parts of the first internal gear ring 11 and the rotating gear 12, reducing wear and extending the life of the transmission components. The bearing between the second internal gear ring 13 and the stirring tank 1 is a high-temperature resistant deep groove ball bearing. The outer ring is fixed to the inner wall of the stirring tank 1, and the inner ring is fitted with the outer edge of the second internal gear ring 13, allowing it to rotate stably under microwave operation. The heat transfer oil circulation loop of the jacket is equipped with a filter and an expansion tank to prevent impurities from clogging the flow channel and to compensate for volume changes caused by thermal expansion and contraction. The control system integrates a PLC module, which can preset and automatically execute the timing, speed, power, temperature, and vacuum parameters of each step from S1 to S9, achieving fully automatic operation. Through the above structure and process, the silicone produced by this invention achieves a mixing uniformity of 98.5%, a moisture content controlled at 45 ppm, no visible bubbles, and no foreign contaminants, fully meeting the performance requirements of silicone materials for high-end electronic packaging such as 5G communication chips and millimeter-wave devices. The entire production process is completed under the synergistic effect of a multi-physical field of fully enclosed, high-vacuum, low-temperature microwave, and precise temperature control, effectively solving the defects of traditional equipment in silicone preparation, such as uneven mixing, incomplete degassing, low dehumidification efficiency, and high risk of contamination.

[0020] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A silicone production equipment for packaging communication chips, comprising a stirring drum (1), wherein the stirring drum (1) is provided with a feed inlet (2) at the top and a discharge valve (3) at the bottom, and a vacuum pump (5) is connected to the top via a vacuum tube (4); a gearbox (6) is fixedly installed on the top side of the stirring drum (1), and a turntable (7) is rotatably provided on the bottom side of the gearbox (6) via a bearing, wherein a main stirring shaft (8) is installed through the center of the turntable (7), and multiple auxiliary stirring shafts (9) are evenly distributed around its periphery; the main stirring shaft (8) is fixedly connected to the turntable (7) and is driven to rotate by a first motor (10) installed on the gearbox (6); the auxiliary stirring shafts (9) are connected to the turntable via a bearing. Rotary connection with turntable (7), with rotating teeth (12) at its upper end, and a first internal gear ring (11) fixedly installed inside the gearbox (6), the rotating teeth (12) meshing with the first internal gear ring (11); a second internal gear ring (13) is rotatably installed on the inner side of the stirring drum (1) through bearings, and a support arm (14) is symmetrically arranged on its bottom side, and several microwave transmitters (15) are installed at equal intervals on the support arm (14); a second motor (16) is provided on the outer wall of the stirring drum (1), and an active tooth (17) is installed at its output end, the active tooth (17) meshing with the second internal gear ring (13); a jacket is provided on the outer wall of the stirring drum (1), and a closed flow channel is formed inside the jacket.

2. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The main stirring shaft (8) and each auxiliary stirring shaft (9) are provided with stirring blades, and the main and auxiliary stirring blades are arranged alternately in the axial and radial directions.

3. The silicone production equipment for communication chip packaging as described in claim 2, characterized in that: The stirring blades of the main stirring shaft (8) and the auxiliary stirring shaft (9) are designed with a spiral angle, and the spiral direction of the main stirring blade is opposite to that of the auxiliary stirring blade.

4. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The number of auxiliary stirring shafts (9) is 3 to 6, and they are distributed at equal angles along the circumference of the turntable (7).

5. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The microwave transmitter (15) operates at a frequency of 2450 MHz and its output power is continuously adjustable from 0 to 2000 W.

6. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The number of microwave transmitters (15) is 4 to 8, and they are arranged at equal intervals along the length of the support arm (14). The axial distance between adjacent microwave transmitters (15) is 50 mm to 100 mm.

7. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The inner wall of the stirring tank (1) is coated with polytetrafluoroethylene.

8. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The vacuum pump (5) is a two-stage rotary vane vacuum pump with an ultimate vacuum of not less than -0.098 MPa and a pumping speed of not less than 120 L / min.

9. The silicone production equipment for communication chip packaging as described in claim 1, characterized in that: The unloading valve (3) is a pneumatic ball valve or an electric butterfly valve; the gearbox (6) is equipped with a lubrication system, including an oil sump, an oil pump and a nozzle, for forced lubrication of the meshing parts of the first internal gear ring (11) and the rotating gear (12).

10. The operating method of a silicone production equipment for communication chip packaging according to claim 7, characterized in that, S1. Open the removable sealing cover of the feed port (2), and put in the raw materials such as A component silica gel, B component silica gel, color paste, and catalyst in sequence. Close the sealing cover and lock the sealing structure to form a closed cavity inside the mixing drum (1). S2. Start the first motor (10) and drive the main stirring shaft (8) to rotate at a speed of 50–100 rpm, which will drive the turntable (7) to revolve and the auxiliary stirring shaft (9) to rotate synchronously to carry out preliminary mixing for 3–5 minutes, so that the components are initially dispersed. S3. Start the vacuum pump (5) and evacuate the inside of the stirring tank (1) through the vacuum tube (4) until the vacuum pressure gauge shows a pressure ≤ -0.095 MPa, and maintain this vacuum level; S4. Increase the speed of the first motor (10) to 300–600 rpm and enter the high-speed compound stirring stage. Under high vacuum, the bubbles inside the material expand rapidly due to the reduction of external pressure. At the same time, affected by the shear force and lifting effect of the stirring blades, the bubbles break and float out along the stirring flow line. The degassing process lasts for 10–20 minutes. S5. Start the second motor (16) and drive the active gear (17) to rotate at a speed of 5–15 rpm, which will drive the microwave transmitter (15) on the second internal gear ring (13) and the support arm (14) to revolve at a constant speed. At the same time, turn on the microwave transmitter (15), set the output power to 800–1500 W, and the irradiation time to 8–15 minutes. The microwave energy penetrates the material layer evenly, causing the water molecules to polarize, generate heat, and evaporate. S6. The jacket temperature control system automatically adjusts the temperature of the heat transfer oil according to the feedback signal from the temperature sensor installed on the inner wall of the mixing drum (1), so that the material temperature is maintained within the process setting range of 40–60℃, and prevents the local temperature from being too high due to microwave heating, which may cause silicone pre-crosslinking or aging. S7. After microwave treatment, turn off the microwave transmitter (15) and the second motor (16), but continue to keep the first motor (10) running and the vacuum pump (5) working for 10–15 minutes to further homogenize the material under vacuum and stirring conditions and eliminate viscosity differences. S8. The jacket is switched to cooling water circulation mode, the cooling water temperature is controlled at 15–25℃, the circulation time is 8–12 minutes, and the material temperature is reduced to below 30℃. S9. Turn off the vacuum pump (5), introduce clean nitrogen into the mixing tank (1) through the air inlet valve to restore the internal pressure to normal pressure, then open the discharge valve (3), and at the same time the first motor (10) runs at a low speed of 30–50 rpm to help the material be discharged smoothly and avoid eddies or secondary air entrainment during the discharge process. Among them, the stirring blades of the main stirring shaft (8) and the auxiliary stirring shaft (9) adopt a spiral angle design, and the spiral direction of the main stirring blade is opposite to that of the auxiliary stirring blade, forming a counter-shear flow field; the number of auxiliary stirring shafts (9) is 3-6, which are distributed at equal angles along the circumference of the turntable (7), and their rotation direction is opposite to their revolution direction, which enhances the material tumbling effect; the number of microwave transmitters (15) is 4-8, which are arranged at equal intervals along the length of the support arm (14), and the axial distance between adjacent microwave transmitters (15) is 50-100mm, ensuring that the material layer also receives uniform microwave irradiation in the height direction; the vacuum pump (5) is a two-stage rotary vane vacuum pump with an ultimate vacuum degree of -0.098 MPa and a pumping rate of not less than 120 L / min, which meets the requirements for quickly establishing a high vacuum environment; the discharge valve (3) is a pneumatic ball valve or an electric butterfly valve with a quick opening and closing function, and the discharge time is controlled within 30 seconds, reducing the material exposure time.

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