Extrusion granulation method of thermoplastic

Abstract

This invention discloses a method for extruding and granulating thermoplastic plastics. The method includes: S1, providing a twin-screw extruder; S2, adjusting the twin-screw extruder; S3, reading the pressure value from a pressure sensor and mapping this pressure value, along with the temperature value from a heating device, to generate standard parameters for the plastic particles; S4, following steps S2 and S3, adjusting the heating temperature and pressure values ​​corresponding to different plastic particles to form a standard adjustment table with a one-to-one correspondence between different plastic particles and their heating temperature and pressure; S5, when plastic particles need to be produced, finding the corresponding pressure value and heating temperature in the standard adjustment table, and then adjusting the length of the kneading zone, the length of the pressurizing zone, or the reverse pressure of the pressurizing zone while monitoring the pressure sensor value in real time. This method can adjust the results of different plastic particle states, and then produce the corresponding plastic particles using the corresponding values, thus improving production efficiency.

Description

Technical Field

[0001] This invention relates to the field of screw extruder technology in plastic particle molding, and more particularly to a twin-screw extruder. Background Technology

[0002] In the production of thermoplastics, twin-screw extruders are required. The main structure of a twin-screw extruder includes a barrel with a feed hopper at one end and a discharge port at the other. A heating device is installed outside the barrel to heat the plastic inside. A first screw and a second screw unit, rotating in the same direction, are mounted inside the barrel. The first and second screw units have identical structures and mesh with each other. The first screw unit has an upstream conveying thread section, a mixing thread section, a kneading thread section, and a downstream conveying thread section. The raw material is conveyed through the upstream conveying thread section and then enters the mixing thread section for mixing. The mixed material is then sheared and dispersed in the kneading thread section before being extruded through the downstream conveying thread section. However, the screw design of current twin-screw extruders is not ideal, and its main problems are... The section consists of a kneading thread, which mainly comprises kneading teeth arranged at 90° intervals. The distance between the ends of the kneading teeth and the inner hole of the barrel is small and uniform. When the kneading teeth rotate, they shear the plastic and disperse the filler in the plastic. However, due to the small and uniform spacing, the plastic is squeezed tightly against the barrel. This causes the plastic in this part to be continuously heated, resulting in an excessively high heating temperature. Consequently, the final extruded plastic melt contains black impurities in the pellets after pelleting. The barrel is equipped with an air extraction port connected to an air extraction pipe. Because some plastic particles are highly viscous, they may adhere to the air extraction port due to the suction force during long-term use. This reduces the area of ​​the air extraction port, affecting the air extraction efficiency. The adhered plastic is also difficult to clean. In addition, current thermoplastic formulations require the addition of inorganic fillers. These fillers need to be sheared and dispersed by kneading teeth to make them into small and uniformly dispersed particles, so that there will be no white spots in the molded plastic particles. However, since the viscosity and flowability of each plastic raw material are different, the degree of dispersion of the filler inside them is different. Therefore, it is necessary to frequently adjust the length and angle of the upstream conveying thread section, mixing thread section, kneading thread section and downstream conveying thread section of the screw, resulting in a very long debugging time. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an extrusion granulation method for thermoplastic plastics, which can adjust the results of different plastic particle states, and then produce corresponding plastic particles by using the corresponding result values, thereby improving production efficiency.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a method for extruding and granulating thermoplastic plastics, comprising the following steps:

[0005] S1. A twin-screw extruder is provided, comprising a base, a barrel fixed on the base, a heating assembly disposed on the outside of the barrel, a first screw unit and a second screw unit rotatably mounted inside the barrel, a rotary power device fixed on the base for driving the first screw unit and the second screw unit to rotate in the same direction, a feed inlet disposed at the upstream end of the barrel, a feeding device disposed at the feed inlet, an upstream conveying area, a mixing area, a kneading area, a pressurizing area and a downstream conveying area disposed sequentially on the barrel, and an extrusion die fixed at the lower end of the barrel, the first screw unit and the second screw unit having the same structure, the first screw unit comprising a first main shaft, on the first main shaft being a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressurizing kneading assembly and a first downstream conveying assembly mounted sequentially by splines in the conveying direction, the corresponding second main shaft being a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressurizing kneading assembly and a second downstream conveying assembly mounted sequentially by splines in the conveying direction;

[0006] The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve, and the second upstream conveying component includes a second upstream conveying threaded sleeve. The first upstream conveying threaded sleeve and the second upstream conveying threaded sleeve mesh with each other.

[0007] The first mixing component includes a first mixing threaded sleeve, and the second mixing component includes a second mixing threaded sleeve. The first mixing threaded sleeve and the second mixing threaded sleeve mesh with each other, and the pitch of the second mixing threaded sleeve is less than the pitch of the first upstream conveying threaded sleeve.

[0008] The first kneading assembly includes a first kneading sleeve, which is splined onto a first main shaft. The first kneading sleeve has several kneading teeth that are staggered at 90° intervals. The tooth surfaces of the kneading teeth are perpendicular to the axis of the first kneading sleeve. The diameter of the outline circle at the outer end of each kneading tooth gradually decreases along the conveying direction. The second kneading assembly has the same structure as the first kneading assembly, and the kneading teeth on the second kneading assembly mesh with the kneading teeth on the first kneading assembly. A pressure sensor for measuring the pressure of the plastic material inside the barrel is fixed on the barrel, and this pressure sensor corresponds to the position of the kneading area.

[0009] The first pressure kneading assembly includes a first pressure engaging sleeve, which is splined onto a first main shaft. The first pressure engaging sleeve has several spaced pressure engaging teeth with an interlacing angle of less than 90°. The diameter of the outline circle at the outer end of each pressure engaging tooth gradually decreases along the conveying direction. The tooth surface of each pressure engaging tooth is perpendicular to the axis of the first kneading sleeve. The second pressure kneading assembly has the same structure as the first pressure kneading assembly, and the pressure engaging teeth on the second pressure kneading assembly mesh with the pressure engaging teeth on the first pressure kneading assembly.

[0010] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0011] The material cylinder is also provided with an air extraction window, and an air extraction box is fixed on the material cylinder at the air extraction window. The air extraction box is provided with an air extraction connector that is connected to the negative pressure air extraction device. The air extraction box is provided with a cleaning device for cleaning the plastic adhering to the air extraction window.

[0012] S2. Debug the twin-screw extruder, including the following steps:

[0013] S21. Add the mixed and stirred raw materials into the feed cylinder from the feeding device;

[0014] S22, the first screw unit and the second screw unit start to rotate in the same direction, the heating device starts to heat, and the raw material passes through the upstream conveying area, mixing area, kneading area, pressurizing area and downstream conveying area in the barrel in sequence before being extruded from the extrusion die;

[0015] S23. The extruded plastic is granulated by a cutter to form plastic particles. The plastic particles are observed. If multiple white spots are found in the plastic particles and the diameter of a single white spot is greater than 0.1 mm, the machine is restarted and adjusted by increasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area until there are no white spots in the plastic particles after extrusion and granulation or the diameter of a single white spot is less than 0.1 mm.

[0016] S3. Read the pressure value of the pressure sensor at this time, and generate the standard parameters of the plastic particle by corresponding the pressure value, the temperature value of the heating device and the plastic particle.

[0017] S4. Following steps S2 and S3, adjust the heating temperature and pressure values ​​corresponding to different plastic particles to form a standard adjustment table that corresponds one-to-one between different plastic particles and heating temperature and pressure.

[0018] S5. When it is necessary to produce plastic particles, find the corresponding pressure value and heating temperature of the plastic particles in the standard debugging table. Then, by increasing or decreasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area, and by monitoring the pressure value of the pressure sensor in real time, normal production can be started when the pressure value reaches the pressure value in the standard debugging table.

[0019] As a preferred solution, when the resistance of the negative pressure suction device rises to a set value, it indicates that the suction window is blocked with plastic material, and a cleaning device is needed to clean the suction window. A cleaning block is vertically and elastically slidably installed above the suction window. When the cleaning device is activated, the cleaning block is released, and the cleaning block quickly inserts into the suction window to clean the plastic material inside, relying on the elastic force of the spring. After cleaning, the cleaning block is driven to rise and detach from the suction window.

[0020] As a preferred embodiment, the cleaning block is installed as follows: the cleaning device includes a mounting plate fixed to the extraction chamber; the cleaning block is coated with polytetrafluoroethylene (PTFE); the shape of the cleaning block matches the shape of the extraction window; at least two guide rods are fixed to the upper end of the cleaning block; the cleaning block is vertically slidably mounted on the mounting plate via the guide rods; a compression spring is fitted on the guide rod, positioned between the cleaning block and the mounting plate; a vertical slot is provided on one of the guide rods; a linear power device is horizontally arranged on the mounting plate; a drive block is fixed to the power end of the linear power device; an inclined drive ramp is provided at the upper end of the drive block; when the cleaning block needs to rise, the drive block moves horizontally and inserts into the vertical slot, pushing the guide rod upward, thereby causing the cleaning block to rise; when the cleaning block needs to descend, the drive block is pulled out from the vertical slot, and the cleaning block is quickly ejected under the action of the compression spring to clean the plastic material adhering to the extraction window.

[0021] As a preferred embodiment, the cleaning device includes a mounting plate fixed to the suction box. A polytetrafluoroethylene (PTFE) coating is adhered to the cleaning block, and the shape of the cleaning block is adapted to the shape of the suction window. At least two guide rods are fixed to the upper end of the cleaning block. The cleaning block is vertically slidably mounted on the mounting plate via the guide rods. A compression spring is fitted onto each guide rod, and the compression spring is positioned between the cleaning block and the mounting plate. The mounting plate is fixed with a swing fulcrum, and a drive swing rod is oscillatingly mounted on the swing fulcrum. The swing fulcrum divides the drive swing rod into short... The device consists of a long arm and a short arm. One of the guide rods has a horizontal strip hole at its upper end. A movable pin is hinged to the long arm and inserted into the horizontal strip hole. A vertical drive cylinder is also fixed on the mounting plate. The piston rod of the vertical drive cylinder is positioned downwards and abuts against the short arm. When the piston rod of the vertical drive cylinder moves downwards, it squeezes the short arm, causing the long arm to lift and drive the guide rod to rise, which in turn drives the cleaning block to rise. When the piston rod of the vertical drive cylinder moves upwards, the cleaning block is quickly ejected downwards under the action of the compression spring to clean the plastic material adhering to the exhaust window.

[0022] As a preferred embodiment, at least one of the spacings between the kneading teeth of the first kneading component is not equal to the other spacings.

[0023] After adopting the above technical solution, the effect of the present invention is: a method for extruding and granulating thermoplastic plastics, comprising the following steps:

[0024] S1. A twin-screw extruder is provided, comprising a base, a barrel fixed on the base, a heating assembly disposed on the outside of the barrel, a first screw unit and a second screw unit rotatably mounted inside the barrel, a rotary power device fixed on the base for driving the first screw unit and the second screw unit to rotate in the same direction, a feed inlet disposed at the upstream end of the barrel, a feeding device disposed at the feed inlet, an upstream conveying area, a mixing area, a kneading area, a pressurizing area and a downstream conveying area disposed sequentially on the barrel, and an extrusion die fixed at the lower end of the barrel, the first screw unit and the second screw unit having the same structure, the first screw unit comprising a first main shaft, on the first main shaft being a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressurizing kneading assembly and a first downstream conveying assembly mounted sequentially by splines in the conveying direction, the corresponding second main shaft being a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressurizing kneading assembly and a second downstream conveying assembly mounted sequentially by splines in the conveying direction;

[0025] The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve, and the second upstream conveying component includes a second upstream conveying threaded sleeve. The first upstream conveying threaded sleeve and the second upstream conveying threaded sleeve mesh with each other.

[0026] The first mixing component includes a first mixing threaded sleeve, and the second mixing component includes a second mixing threaded sleeve. The first mixing threaded sleeve and the second mixing threaded sleeve mesh with each other, and the pitch of the second mixing threaded sleeve is less than the pitch of the first upstream conveying threaded sleeve.

[0027] The first kneading assembly includes a first kneading sleeve, which is splined onto a first main shaft. The first kneading sleeve has several kneading teeth that are staggered at 90° intervals. The tooth surfaces of the kneading teeth are perpendicular to the axis of the first kneading sleeve. The diameter of the outline circle at the outer end of each kneading tooth gradually decreases along the conveying direction. The second kneading assembly has the same structure as the first kneading assembly, and the kneading teeth on the second kneading assembly mesh with the kneading teeth on the first kneading assembly. A pressure sensor for measuring the pressure of the plastic material inside the barrel is fixed on the barrel, and this pressure sensor corresponds to the position of the kneading area.

[0028] The first pressure kneading assembly includes a first pressure engaging sleeve, which is splined onto a first main shaft. The first pressure engaging sleeve has several spaced pressure engaging teeth with an interlacing angle of less than 90°. The diameter of the outline circle at the outer end of each pressure engaging tooth gradually decreases along the conveying direction. The tooth surface of each pressure engaging tooth is perpendicular to the axis of the first kneading sleeve. The second pressure kneading assembly has the same structure as the first pressure kneading assembly, and the pressure engaging teeth on the second pressure kneading assembly mesh with the pressure engaging teeth on the first pressure kneading assembly.

[0029] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0030] The material cylinder is also provided with an air extraction window, and an air extraction box is fixed on the material cylinder at the air extraction window. The air extraction box is provided with an air extraction connector that is connected to the negative pressure air extraction device. The air extraction box is provided with a cleaning device for cleaning the plastic adhering to the air extraction window.

[0031] S2. Debug the twin-screw extruder, including the following steps:

[0032] S21. Add the mixed and stirred raw materials into the feed cylinder from the feeding device;

[0033] S22, the first screw unit and the second screw unit start to rotate in the same direction, the heating device starts to heat, and the raw material passes through the upstream conveying area, mixing area, kneading area, pressurizing area and downstream conveying area in the barrel in sequence before being extruded from the extrusion die;

[0034] S23. The extruded plastic is granulated by a cutter to form plastic particles. The plastic particles are observed. If multiple white spots are found in the plastic particles and the diameter of a single white spot is greater than 0.1 mm, the machine is restarted and adjusted by increasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area until there are no white spots in the plastic particles after extrusion and granulation or the diameter of a single white spot is less than 0.1 mm.

[0035] S3. Read the pressure value from the pressure sensor at this time, and generate the standard parameters for the plastic particle by matching the pressure value, the temperature value of the heating device, and the plastic particle itself.

[0036] S4. Following steps S2 and S3, adjust the heating temperature and pressure values ​​corresponding to different plastic particles to form a standard adjustment table that corresponds one-to-one between different plastic particles and heating temperature and pressure.

[0037] S5. When it is necessary to produce plastic particles, find the corresponding pressure value and heating temperature of the plastic particles in the standard debugging table, and then increase or decrease the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area, and monitor the pressure value of the pressure sensor in real time. When the pressure value reaches the pressure value in the standard debugging table, normal production can begin.

[0038] This way, the required production values ​​for plastic particles can be obtained through a series of adjustments. Then, the corresponding plastic particles can be produced simply by setting the required production values. This makes it easier to produce different types of plastic particles, improves production efficiency, and makes adjustments more convenient.

[0039] Furthermore, when the resistance of the negative pressure suction device rises to the set value, it indicates that the suction window is blocked by plastic material. At this time, a cleaning device is needed to clean the suction window. A cleaning block is vertically and elastically slidably installed above the suction window. When the cleaning device is activated, the cleaning block is released, and the cleaning block quickly inserts into the suction window to clean the plastic material inside, relying on the elastic force of the spring. After cleaning, the cleaning block is driven to rise and detach from the suction window. The compression of the spring can accelerate the descent speed, thereby quickly cleaning the material adhering to it, improving the cleaning effect. Moreover, the detachment of the cleaning block from the window facilitates negative pressure suction, ensuring the effectiveness of use.

[0040] Furthermore, the installation method of the cleaning block is as follows: the cleaning device includes a mounting plate fixed to the extraction box; the cleaning block is coated with polytetrafluoroethylene; the shape of the cleaning block matches the shape of the extraction window; at least two guide rods are fixed to the upper end of the cleaning block; the cleaning block is vertically slidably mounted on the mounting plate via the guide rods; a compression spring is fitted on the guide rod, and the compression spring is positioned between the cleaning block and the mounting plate; one of the guide rods has a vertical strip hole; and a linear power device is horizontally arranged on the mounting plate. A drive block is fixed to the power end of the linear power device. The upper end of the drive block is provided with an inclined drive ramp. When the cleaning block needs to rise, the drive block moves horizontally and inserts into the vertical strip hole, pushing the guide rod upward, thereby driving the cleaning block to rise. When the cleaning block needs to descend, the drive block is pulled out from the vertical strip hole, and the cleaning block is quickly ejected under the action of the compression spring to clean the plastic material adhering in the air extraction window. The linear power device drives the drive block to move, thereby cooperating with the vertical strip hole to raise and lower the guide rod, thus enabling the cleaning block to rise and fall effectively. The structure is simple and reliable.

[0041] Furthermore, the cleaning device includes a mounting plate fixed to the extraction chamber. The cleaning block is coated with polytetrafluoroethylene (PTFE). The shape of the cleaning block matches the shape of the extraction window. At least two guide rods are fixed to the upper end of the cleaning block. The cleaning block is vertically slidably mounted on the mounting plate via the guide rods. A compression spring is fitted on the guide rod, positioned between the cleaning block and the mounting plate. The mounting plate is fixed with a swing fulcrum. A drive swing rod is oscillatingly mounted on the swing fulcrum, dividing the drive swing rod into a short arm and a long arm. A horizontal strip hole is provided at the upper end of one of the guide rods. A movable pin is hinged to the long arm. The moving pin is inserted into the horizontal strip hole. A vertical drive cylinder is also fixed on the mounting plate. The piston rod of the vertical drive cylinder is set downward and abuts against the short arm. When the piston rod of the vertical drive cylinder moves downward, it squeezes the short arm, thereby causing the long arm to lift and drive the guide rod to rise, which in turn drives the cleaning block to rise. When the piston rod of the vertical drive cylinder moves upward, the cleaning block is quickly ejected downward under the action of the compression spring to clean the plastic material adhering to the exhaust window. In this way, the extension and retraction of the vertical drive cylinder can drive the extension and retraction of the piston rod, thereby causing the drive swing rod to swing. The cleaning block can be effectively raised and lowered. The structure is simple and reliable, and it can also easily clean the plastic material adhering to the exhaust window.

[0042] Furthermore, since at least one of the spacings between the kneading teeth of the first kneading component is not equal to the other spacings, the plastic can flow between the meshing teeth, effectively improving the shearing and dispersion effect, and enabling the plastic to be accurately and effectively transported. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] Figure 1 This is a perspective view of an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of the first screw unit and the second screw unit in an embodiment of the present invention;

[0046] Figure 3 This is a half-sectional view of the first screw unit and the second screw unit according to an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the structure of the first kneading component, the first pressure kneading component, the second kneading component, and the second pressure kneading component in an embodiment of the present invention.

[0048] Figure 5 This is a structure inside the air extraction box in an embodiment of the present invention;

[0049] Figure 6 This is another structure inside the air extraction box in an embodiment of the present invention;

[0050] In the attached diagram: 1. Machine base; 2. Feed inlet; 3. Feeding device; 4. Extrusion die; 5. Rotary motor; 6. Barrel; 7. First main shaft; 8. Second main shaft; 9. Spline; 10. First upstream conveying threaded sleeve; 11. Second upstream conveying threaded sleeve; 12. First mixing threaded sleeve; 13. Second mixing threaded sleeve; 14. First kneading sleeve; 15. Kneading teeth; 16. Second kneading sleeve; 17. First pressure engaging sleeve; 18. Pressure engaging teeth; 19. Second pressure engaging sleeve; 20. First 21. Downstream conveying threaded sleeve; 22. Second downstream conveying threaded sleeve; 23. Groove; 24. Air extraction window; 25. Air extraction box; 26. Horizontal linear cylinder; 27. Air extraction connector; 28. Cleaning block; 29. ​​Mounting plate; 30. Guide rod; 31. Compression spring; 32. Drive block; 33. Drive inclined plane; 34. Vertical strip hole; 35. Limit nut; 36. Swing fulcrum; 37. Drive swing rod; 38. Horizontal strip hole; 39. Movable pin; 40. Vertical drive cylinder; 41. Drive roller. Detailed Implementation

[0051] The present invention will be further described in detail below through specific embodiments.

[0052] like Figures 1 to 6 As shown, a method for extruding and granulating thermoplastics includes the following steps:

[0053] S1. A twin-screw extruder is provided, comprising a base 1, a barrel 6 fixed on the base 1, a heating assembly externally mounted on the barrel 6, a first screw unit and a second screw unit rotatably mounted inside the barrel 6, a rotary power device fixed on the base 1 to drive the first screw unit and the second screw unit to rotate in the same direction, a feed inlet 2 provided at the upstream end of the barrel 6, a feeding device 3 provided at the feed inlet 2, and an upstream conveying area, a mixing area, a kneading area, a pressurizing area and a downstream conveying area sequentially arranged on the barrel 6. The lower end of the barrel 6 is fixed with an extrusion die 4. The first screw unit and the second screw unit have the same structure. The first screw unit includes a first main shaft 7. The first main shaft 7 is equipped with a first upstream conveying component, a first mixing component, a first kneading component, a first pressurized kneading component and a first downstream conveying component in the conveying direction through a spline 9. Correspondingly, the second main shaft 8 is equipped with a second upstream conveying component, a second mixing component, a second kneading component, a second pressurized kneading component and a second downstream conveying component in the conveying direction through a spline 9.

[0054] The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve 10 and the second upstream conveying component includes a second upstream conveying threaded sleeve 11. The first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 mesh with each other.

[0055] The first mixing component includes a first mixing threaded sleeve 12, and the second mixing component includes a second mixing threaded sleeve 13. The first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 mesh with each other, and the pitch of the second mixing threaded sleeve 13 is less than the pitch of the first upstream conveying threaded sleeve 10.

[0056] The first kneading assembly includes a first kneading sleeve 14, which is mounted on the first main shaft 7 via a spline 9. The first kneading sleeve 14 has a plurality of kneading teeth 15 arranged at 90° intervals, the tooth surfaces of which are perpendicular to the axis of the first kneading sleeve 14. The diameter of the outline circle at the outer end of each kneading tooth 15 gradually decreases along the conveying direction. The structure of the second kneading assembly is the same as that of the first kneading assembly, and the kneading teeth 15 on the second kneading assembly mesh with those on the first kneading assembly. A pressure sensor for measuring the pressure of the plastic material inside the material cylinder 6 is fixed on the cylinder 6, and this pressure sensor corresponds to the position of the kneading area.

[0057] The first pressure kneading assembly includes a first pressure engaging sleeve 17, which is mounted on the first main shaft 7 via a spline 9. The first pressure engaging sleeve 17 is provided with a plurality of spaced pressure engaging teeth 18, the stagger angle of which is less than 90°. The diameter of the contour circle at the outer end of each pressure engaging tooth 18 gradually decreases according to the conveying direction. The tooth surface of the pressure engaging teeth 18 is perpendicular to the axis of the first kneading sleeve 14. The structure of the second pressure kneading assembly is the same as that of the first pressure kneading assembly. The pressure engaging teeth 18 on the second pressure kneading assembly mesh with the pressure engaging teeth 18 on the first pressure kneading assembly.

[0058] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0059] The material cylinder 6 is also provided with an air extraction window 23. An air extraction box 24 is fixed on the material cylinder 6 at the air extraction window 23. An air extraction connector 26 connected to the negative pressure air extraction device is provided on the air extraction box 24. A cleaning device for cleaning the plastic adhering to the air extraction window 23 is provided inside the air extraction box 24.

[0060] S2. Debug the twin-screw extruder, including the following steps:

[0061] S21. The mixed raw materials are added into the feed cylinder 6 from the feeding device 3;

[0062] S22, the first screw unit and the second screw unit start to rotate in the same direction, the heating device starts to heat, and the raw material passes through the upstream conveying area, mixing area, kneading area, pressurizing area and downstream conveying area in the barrel 6 in sequence before being extruded from the extrusion die 4.

[0063] S23. The extruded plastic is granulated by a cutter to form plastic particles. The plastic particles are observed. If multiple white spots are found in the plastic particles and the diameter of a single white spot is greater than 0.1 mm, the machine is restarted and adjusted by increasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area until there are no white spots in the plastic particles after extrusion and granulation or the diameter of a single white spot is less than 0.1 mm.

[0064] S3. Read the pressure value of the pressure sensor at this time, and generate the standard parameters of the plastic particle by corresponding the pressure value, the temperature value of the heating device and the plastic particle.

[0065] S4. Following steps S2 and S3, adjust the heating temperature and pressure values ​​corresponding to different plastic particles to form a standard adjustment table that corresponds one-to-one between different plastic particles and heating temperature and pressure.

[0066] S5. When it is necessary to produce plastic particles, find the corresponding pressure value and heating temperature of the plastic particles in the standard debugging table. Then, by increasing or decreasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area, and by monitoring the pressure value of the pressure sensor in real time, normal production can be started when the pressure value reaches the pressure value in the standard debugging table. In this way, the required production value of plastic particles can be obtained through a series of debugging. Then, the corresponding plastic particles can be produced by simply setting the required production value, which is convenient for producing different plastic particles and improving production efficiency.

[0067] Preferably, when the resistance of the negative pressure suction device rises to a set value, it indicates that the suction window 23 is blocked with plastic material, and a cleaning device is needed to clean the suction window 23. A cleaning block 27 is vertically and elastically slidably installed above the suction window 23. When the cleaning device is started, the cleaning block 27 is released, and the cleaning block 27 quickly inserts into the suction window 23 to clean the plastic material inside, relying on the elastic force of the spring. After cleaning, the cleaning block 27 is driven to rise and detach from the suction window 23. The compression spring 30 can accelerate the descent speed, thereby quickly cleaning the material adhering to it, improving the cleaning effect, and the detachment of the cleaning block 27 from the window facilitates negative pressure suction, ensuring the effect of use.

[0068] Preferably, the cleaning block 27 is installed as follows: the cleaning device includes a mounting plate 28 fixed to the extraction box 24; the cleaning block 27 is coated with polytetrafluoroethylene; the shape of the cleaning block 27 is adapted to the shape of the extraction window 23; at least two guide rods 29 are fixed to the upper end of the cleaning block 27; the cleaning block 27 is vertically slidably mounted on the mounting plate 28 via the guide rods 29; a compression spring 30 is fitted on the guide rod 29 and is disposed between the cleaning block 27 and the mounting plate 28; a vertical strip hole 33 is provided on one of the guide rods 29; and a linear power device is horizontally arranged on the mounting plate 28; the power end of the linear power device... A drive block 31 is fixed in place, and an inclined drive ramp 32 is provided at the upper end of the drive block 31. When the cleaning block 27 needs to rise, the drive block 31 moves horizontally and inserts into the vertical strip hole 33, pushing the guide rod 29 upward, thereby driving the cleaning block 27 to rise. When the cleaning block 27 needs to fall, the drive block 31 is pulled out from the vertical strip hole 33, and the cleaning block is quickly ejected under the action of the compression spring 30 to clean the plastic material adhering in the air extraction window 23. The polytetrafluoroethylene coating can effectively prevent the cleaning block 27 from sticking to the plastic material. The drive block 31 is driven to move by a linear power device, thereby cooperating with the vertical strip hole 33 to raise and lower the guide rod 29, so that the cleaning block 27 can be effectively raised and lowered. The structure is simple and reliable.

[0069] Preferably, the cleaning device includes a mounting plate 28 fixed to the suction box 24. The cleaning block 27 has a polytetrafluoroethylene coating adhered to it. The shape of the cleaning block 27 matches the shape of the suction window 23. At least two guide rods 29 are fixed to the upper end of the cleaning block 27. The cleaning block 27 is vertically slidably mounted on the mounting plate 28 via the guide rods 29. A compression spring 30 is fitted onto the guide rod 29, positioned between the cleaning block 27 and the mounting plate 28. The mounting plate 28 has a fixed swing fulcrum 35. A drive swing rod 36 is swayingly mounted on the swing fulcrum 35, dividing the drive swing rod 36 into a short arm and a long arm. A horizontal strip hole 37 is provided at the upper end of one of the guide rods 29. A movable pin 38 is hinged to the long arm. 8 is inserted into the horizontal strip hole 37. A vertical drive cylinder 39 is also fixed on the mounting plate 28. The piston rod of the vertical drive cylinder 39 is set downward and abuts against the short arm. When the piston rod of the vertical drive cylinder 39 moves downward, it squeezes the short arm, thereby causing the long arm to lift up and drive the guide rod 29 to rise, which in turn drives the cleaning block 27 to rise. When the piston rod of the vertical drive cylinder 39 moves upward, the cleaning block 27 is quickly ejected downward under the action of the compression spring 30 to clean the plastic material adhering to the exhaust window 23. The polytetrafluoroethylene coating can effectively prevent the cleaning block 27 from sticking to the plastic material. In this way, the extension and retraction of the vertical drive cylinder 39 can drive the extension and retraction of the piston rod, thereby causing the drive swing rod 36 to swing. The cleaning block 27 can be effectively raised and lowered. The structure is simple and reliable, and it can also easily clean the plastic material adhering to the exhaust window 23.

[0070] Preferably, at least one of the spacings between the kneading teeth 15 of the first kneading component is different from the other spacings; this allows the plastic to flow between the kneading teeth, effectively improving the shearing and dispersion effect, and enabling the plastic to be accurately and effectively transported.

[0071] In addition, embodiments of the present invention also disclose a twin-screw extruder, such as Figures 1 to 6As shown, a twin-screw extruder includes a base 1, on which a barrel 6 is fixed. A first screw unit and a second screw unit are rotatably mounted inside the barrel 6. A rotary power device for driving the first screw unit and the second screw unit to rotate in the same direction is fixed on the base 1. A feed inlet 2 is provided at the upstream end of the barrel 6, and a feeding device 3 is provided at the feed inlet 2. An extrusion die 4 is fixed at the lower end of the barrel 6. The first screw unit and the second screw unit have the same structure. The first screw unit includes a first main shaft 7. A first upstream conveying component, a first mixing component, a first kneading component, a first pressurized kneading component, and a first downstream conveying component are mounted on the first main shaft 7 in the conveying direction via splines 9. Correspondingly, a second upstream conveying component, a second mixing component, a second kneading component, a second pressurized kneading component, and a second downstream conveying component are mounted on the second main shaft 8 in the conveying direction via splines 9.

[0072] The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve 10 and the second upstream conveying component includes a second upstream conveying threaded sleeve 11. The first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 mesh with each other.

[0073] The first mixing component includes a first mixing threaded sleeve 12, and the second mixing component includes a second mixing threaded sleeve 13. The first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 mesh with each other, and the pitch of the second mixing threaded sleeve 13 is less than the pitch of the first upstream conveying threaded sleeve 10.

[0074] The first kneading assembly includes a first kneading sleeve 14, which is mounted on the first main shaft 7 via a spline 9. The first kneading sleeve 14 is provided with a plurality of kneading teeth 15 that are staggered at 90° and spaced apart. The tooth surface of the kneading teeth 15 is perpendicular to the axis of the first kneading sleeve 14. The diameter of the contour circle at the outer end of each kneading tooth 15 gradually decreases according to the conveying direction. The structure of the second kneading assembly is the same as that of the first kneading assembly. The kneading teeth 15 on the second kneading assembly mesh with the kneading teeth 15 on the first kneading assembly. The second kneading assembly includes a second kneading sleeve 16.

[0075] The first pressure kneading assembly includes a first pressure engaging sleeve 17, which is mounted on the first main shaft 7 via a spline 9. The first pressure engaging sleeve 17 has several spaced pressure engaging teeth 18, with an interleaving angle of less than 90°. The diameter of the outline circle at the outer end of each pressure engaging tooth 18 gradually decreases along the conveying direction. The tooth surface of each pressure engaging tooth 18 is perpendicular to the axis of the first kneading sleeve 14. The second pressure kneading assembly has the same structure as the first pressure kneading assembly, and the pressure engaging teeth 18 on the second pressure kneading assembly mesh with the pressure engaging teeth 18 on the first pressure kneading assembly. The second pressure kneading assembly includes a second pressure engaging sleeve 19.

[0076] The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly;

[0077] The feeding device 3 first feeds the plastic raw material into the feed port 2. A rotary power device drives the first and second screw units to rotate in the same direction. This rotary power device includes a rotary motor 5, which is mounted on the base 1 and drives the first main shaft 7 and the second main shaft 8 to rotate in the same direction. The first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11 initially convey and initially compress the plastic, causing it to initially disperse. Then, the first mixing threaded sleeve 12 and the second mixing threaded sleeve 13 further compress and disperse the plastic on the basis of the previous steps, while simultaneously slowing down the conveying speed. Then, the plastic is further sheared and dispersed by several kneading teeth 15 arranged at 90° intervals, resulting in more uniform shearing and dispersion. The diameter of the outline circle at the outer end of each kneading tooth 15 gradually decreases along the conveying direction, which facilitates the smooth passage of the plastic through this area and, in particular, avoids prolonged plastic stagnation. The temperature on the wall of the barrel 6 is too high; in addition, the stagger angle of the pressure meshing teeth 18 is small, and the diameter of the outline circle at the outer end of each pressure meshing tooth 18 gradually decreases along the conveying direction. In this way, the pressure meshing teeth 18 can increase the flow resistance of the plastic in this area. This increases the distance between the pressure meshing teeth 18 and the inside of the barrel 6, while further controlling and extending the shearing and dispersion time, ensuring the shearing and dispersion effect of the plastic raw material and reducing the generation of impurities. Finally, the plastic after shearing and dispersion is conveyed out by the first downstream conveying assembly and the second downstream conveying assembly. The first downstream conveying assembly includes the first downstream conveying threaded sleeve 20, and the second downstream conveying assembly includes the second downstream conveying threaded sleeve 21. The first downstream conveying threaded sleeve 20 and the second downstream conveying threaded sleeve 21 are the same as the first upstream conveying threaded sleeve 10 and the second upstream conveying threaded sleeve 11, which extrudes and conveys the plastic after shearing and dispersion.

[0078] The material cylinder 6 is also provided with an air extraction window 23. An air extraction box 24 is fixed on the material cylinder 6 at the air extraction window 23. An air extraction connector 26 connected to a negative pressure air extraction device is provided on the air extraction box 24. A cleaning device is provided inside the air extraction box 24 to clean the plastic adhering to the air extraction window 23. The plastic adhering to the air extraction window 23 is cleaned by the cleaning device, and then the air is extracted from the inside of the material cylinder 6 through the air extraction connector 26.

[0079] like Figure 5 As shown, the cleaning device includes a cleaning block 27 vertically and vertically installed inside the suction box 24. The cleaning block 27 is coated with polytetrafluoroethylene. The shape of the cleaning block 27 is adapted to the shape of the suction window 23. The cleaning block 27 is driven by a vertical lifting power device to be inserted into the suction window 23 from top to bottom. When the cleaning block 27 is in the uppermost position, it is detached from the suction window 23. Because the cleaning block is adapted to the shape of the suction window 23, the plastic adhering to the suction window 23 can be squeezed and cleaned, which is simple and quick. Furthermore, when the cleaning block 27 is in the uppermost position, it is detached from the suction window 23, which facilitates suction after cleaning.

[0080] Furthermore, an installation plate 28 is fixed on the suction box 24, and at least two guide rods 29 are fixed to the upper end of the cleaning block 27. The cleaning block 27 is vertically slidably mounted on the installation plate 28 via the guide rods 29. A compression spring 30 is fitted on the guide rod 29, and the compression spring 30 is disposed between the cleaning block 27 and the installation plate 28. The vertical lifting power device is fixed on the installation plate 28. The vertical lifting power device can drive the cleaning block 27 to rise, and the cleaning block 27 can cooperate with the installation plate 28 to compress the compression spring 30. When the cleaning block 27 descends, the compression spring 30 can accelerate the descent speed to quickly clean the material attachments and improve the cleaning effect. The guide rods 29 can ensure the stability of the lifting of the cleaning block 27 and ensure its use.

[0081] In this embodiment, the vertical lifting power device includes a linear power device fixed to the mounting plate 28 and arranged horizontally. A drive block 31 is fixed to the power end of the linear power device. An inclined drive ramp 32 is provided at the upper end of the drive block 31. A vertical strip hole 33 is provided on one of the guide rods 29 to cooperate with the drive ramp 32 of the drive block 31. A limiting structure is provided on the other guide rod 29 to limit the descent limit position of the cleaning block 27. The linear power device drives the drive block 31 to move linearly, which in turn drives the guide rod 29 to rise and fall by cooperating with the vertical strip hole 33. The drive ramp 32 can slowly push up the vertical strip hole 33, thereby controlling the compression of the compression spring 30. At the same time, the limiting structure can prevent the cleaning block 27 from falling too far, ensuring the effect of use. The linear power device is a horizontal linear cylinder 25, which drives the drive block 31 to move horizontally.

[0082] Furthermore, the limiting structure is a limiting nut 34 fixed on the guide rod 29. When the limiting nut 34 contacts and engages with the upper surface of the mounting plate 28, the upper end of the vertical strip hole 33 is higher than the upper surface of the mounting plate 28. In this way, when the drive block 31 moves, it can be effectively inserted into the vertical strip hole 33 to make the cleaning block 27 rise, ensuring the effect of use.

[0083] like Figure 6 As shown, the vertical lifting power device includes a swing fulcrum 35 fixed on the mounting plate 28. A drive swing rod 36 is swayingly mounted on the swing fulcrum 35, dividing the drive swing rod 36 into a short arm and a long arm. The upper end of a guide rod 29 is provided with a horizontal strip hole 37. A movable pin 38 is hinged to the long arm and inserted into the horizontal strip hole 37. A vertical drive cylinder 39 is also fixed on the mounting plate 28. The piston rod of the vertical drive cylinder 39 is set downward and abuts against the short arm. By extending and retracting the piston of the vertical cylinder, the up and down swing of the short arm can be controlled, thereby causing the long arm to swing up and down. The guide rod 29 can be raised and lowered by moving the movable pin 38 horizontally within the horizontal strip hole 37, so that the cleaning block 27 can be effectively raised and lowered. The structure is simple and reliable.

[0084] Furthermore, a drive roller 40 is mounted on the piston rod of the vertical drive cylinder 39; this allows for flexible contact with the short arm, reducing friction and improving efficiency.

[0085] In this embodiment, the interlacing angle of the pressure meshing teeth 18 is 60°. The smaller the interlacing angle, the better the shearing and dispersion effect. Therefore, the pressure meshing teeth 18 can effectively increase the flow resistance of the plastic in this area, so that the plastic can be sheared and dispersed more evenly. This avoids excessive flow resistance, slow conveying and affecting processing efficiency.

[0086] Furthermore, at least one of the spacings between the kneading teeth 15 of the first kneading component is not equal to the other spacings; this allows the plastic to flow between the kneading teeth, effectively improving the shearing and dispersion effect, and enabling the plastic to be accurately and effectively transported.

[0087] like Figure 2 As shown, the first hybrid threaded sleeve 12 has radially extending grooves 22 on its threads; this effectively improves the shearing capacity of the first hybrid threaded sleeve 12. At the same time, the second hybrid threaded sleeve 13 also has corresponding grooves 22, so that preliminary shearing can be performed before shearing, thus improving the shearing dispersion effect.

[0088] Furthermore, the number of the first kneading components is one or more, and the number of the first pressure kneading components is one or more; the more first kneading components and first pressure kneading components there are, the better the shearing and dispersion effect on the plastic will be, effectively improving the quality of production.

[0089] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications and alterations made to the technical solutions of the present invention without departing from the spirit of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A method of extrusion granulation of thermoplastics, characterized in that: Includes the following steps: S1. A twin-screw extruder is provided, comprising a base, a barrel fixed on the base, a heating assembly disposed on the outside of the barrel, a first screw unit and a second screw unit rotatably mounted inside the barrel, a rotary power device fixed on the base for driving the first screw unit and the second screw unit to rotate in the same direction, a feed inlet disposed at the upstream end of the barrel, a feeding device disposed at the feed inlet, an upstream conveying area, a mixing area, a kneading area, a pressurizing area and a downstream conveying area disposed sequentially on the barrel, and an extrusion die fixed at the lower end of the barrel, the first screw unit and the second screw unit having the same structure, the first screw unit comprising a first main shaft, on the first main shaft being a first upstream conveying assembly, a first mixing assembly, a first kneading assembly, a first pressurizing kneading assembly and a first downstream conveying assembly mounted sequentially by splines in the conveying direction, the corresponding second main shaft being a second upstream conveying assembly, a second mixing assembly, a second kneading assembly, a second pressurizing kneading assembly and a second downstream conveying assembly mounted sequentially by splines in the conveying direction; The first upstream conveying component and the second upstream conveying component have the same structure. The first upstream conveying component includes a first upstream conveying threaded sleeve, and the second upstream conveying component includes a second upstream conveying threaded sleeve. The first upstream conveying threaded sleeve and the second upstream conveying threaded sleeve mesh with each other. The first mixing component includes a first mixing threaded sleeve, and the second mixing component includes a second mixing threaded sleeve. The first mixing threaded sleeve and the second mixing threaded sleeve mesh with each other, and the pitch of the second mixing threaded sleeve is less than the pitch of the first upstream conveying threaded sleeve. The first kneading assembly includes a first kneading sleeve, which is splined onto a first main shaft. The first kneading sleeve has several kneading teeth that are staggered at 90° intervals. The tooth surfaces of the kneading teeth are perpendicular to the axis of the first kneading sleeve. The diameter of the outline circle at the outer end of each kneading tooth gradually decreases along the conveying direction. The second kneading assembly has the same structure as the first kneading assembly, and the kneading teeth on the second kneading assembly mesh with the kneading teeth on the first kneading assembly. A pressure sensor for measuring the pressure of the plastic material inside the barrel is fixed on the barrel, and this pressure sensor corresponds to the position of the kneading area. The first pressure kneading assembly includes a first pressure engaging sleeve, which is splined onto a first main shaft. The first pressure engaging sleeve has several spaced pressure engaging teeth with an interlacing angle of less than 90°. The diameter of the outline circle at the outer end of each pressure engaging tooth gradually decreases along the conveying direction. The tooth surface of each pressure engaging tooth is perpendicular to the axis of the first kneading sleeve. The second pressure kneading assembly has the same structure as the first pressure kneading assembly, and the pressure engaging teeth on the second pressure kneading assembly mesh with the pressure engaging teeth on the first pressure kneading assembly. The structure of the first downstream conveying assembly is the same as that of the first upstream conveying assembly, and the structure of the second downstream conveying assembly is the same as that of the second upstream conveying assembly; The material cylinder is also provided with an air extraction window, and an air extraction box is fixed on the material cylinder at the air extraction window. The air extraction box is provided with an air extraction connector that is connected to the negative pressure air extraction device. The air extraction box is provided with a cleaning device for cleaning the plastic adhering to the air extraction window. S2. Debug the twin-screw extruder, including the following steps: S21. Add the mixed and stirred raw materials into the feed cylinder from the feeding device; S22, the first screw unit and the second screw unit start to rotate in the same direction, the heating device starts to heat, and the raw material passes through the upstream conveying area, mixing area, kneading area, pressurizing area and downstream conveying area in the barrel in sequence before being extruded from the extrusion die; S23. Extruded plastic is granulated by a cutter to form plastic particles; If multiple white spots are found in the plastic particles and the diameter of a single white spot is greater than 0.1 mm, the machine is restarted and adjusted by increasing the length of the kneading area or the length of the pressurizing area or the reverse pressure of the pressurizing area until there are no white spots in the extruded and pelletized plastic particles or the diameter of a single white spot is less than 0.1 mm. S3. Read the pressure value of the pressure sensor at this time, and generate the standard parameters of the plastic particle by corresponding the pressure value, the temperature value of the heating device and the plastic particle. S4. Following steps S2 and S3, adjust the heating temperature and pressure values ​​corresponding to different plastic particles to form a standard adjustment table that corresponds one-to-one between different plastic particles and heating temperature and pressure. S5. When producing plastic granules, find the corresponding pressure value and heating temperature for that plastic granule in the standard calibration table. Then, by increasing or decreasing the length of the kneading zone, the length of the pressurizing zone, or the reverse pressure of the pressurizing zone, and by monitoring the pressure sensor value in real time, normal production can begin once the pressure value reaches the value specified in the standard calibration table. When the resistance of the negative pressure suction device rises to the set value, it indicates that the suction window is blocked with plastic material. At this point, a cleaning device is needed to clean the suction window. A cleaning block is vertically and elastically slidably installed above the suction window. When the cleaning device is activated, the cleaning block is released, and the block, relying on the spring force, quickly inserts into the suction window to clean the plastic material inside. After cleaning, the cleaning block is lifted and detached from the suction window. The cleaning block is installed as follows: the cleaning device includes a mounting plate fixed to the extraction box. The cleaning block is coated with polytetrafluoroethylene (PTFE). The shape of the cleaning block matches the shape of the extraction window. At least two guide rods are fixed to the upper end of the cleaning block. The cleaning block is vertically slidably mounted on the mounting plate via the guide rods. A compression spring is fitted on the guide rod, which is positioned between the cleaning block and the mounting plate. One of the guide rods has a vertical slot. A linear power device is horizontally arranged on the mounting plate. A drive block is fixed to the power end of the linear power device. An inclined drive ramp is provided at the upper end of the drive block. When the cleaning block needs to rise, the drive block moves horizontally and inserts into the vertical slot, pushing the guide rod upward, thereby causing the cleaning block to rise. When the cleaning block needs to descend, the drive block is pulled out from the vertical slot, and the cleaning block is quickly ejected under the action of the compression spring to clean the plastic material adhering to the extraction window.

2. The extrusion granulation method for thermoplastic plastics as described in claim 1, characterized in that: The cleaning device includes a mounting plate fixed to the extraction chamber. A polytetrafluoroethylene (PTFE) coating is adhered to the cleaning block, and the shape of the cleaning block is adapted to the shape of the extraction window. At least two guide rods are fixed to the upper end of the cleaning block. The cleaning block is vertically slidably mounted on the mounting plate via the guide rods. A compression spring is fitted onto each guide rod, and the compression spring is positioned between the cleaning block and the mounting plate. The mounting plate is fixed with a swing fulcrum, on which a drive swing rod is oscillatingly mounted. The swing fulcrum divides the drive swing rod into a short arm and a long arm. One of the guide rods has a horizontal slot at its upper end. A movable pin is hinged to the long arm and inserted into the horizontal slot. A vertical drive cylinder is also fixed on the mounting plate. The piston rod of the vertical drive cylinder is positioned downward and abuts against the short arm. When the piston rod of the vertical drive cylinder moves downward, it squeezes the short arm, causing the long arm to lift and drive the guide rod to rise, which in turn drives the cleaning block to rise. When the piston rod of the vertical drive cylinder moves upward, the cleaning block is quickly ejected downward under the action of the compression spring to clean the plastic material adhering to the exhaust window.

3. The extrusion granulation method for thermoplastic plastics as described in claim 2, characterized in that: In the first kneading component, at least one of the kneading teeth has a spacing that is not equal to the other spacings.

Images