Supercritical fluid assisted high polymer material extrusion molding machine

Abstract

The invention discloses a supercritical fluid assisted high polymer material extrusion molding machine, and relates to the technical field of plastic extrusion molding, the supercritical fluid assisted high polymer material extrusion molding machine comprises a molding unit and a supercritical fluid supply unit, the molding unit comprises a charging barrel, a screw rod and a driving mechanism, and the driving mechanism is used for driving the screw rod to rotate in the charging barrel; the charging barrel is provided with a supercritical fluid input hole, and the input hole is used for injecting supercritical fluid into the supercritical fluid supply unit; the material barrel is provided with a bypass pipe, the two ends of the bypass pipe are fixedly connected with the material barrel and communicated with an inner cavity of the material barrel, the bypass pipe is a thin-wall metal pipe, the inner diameter of the bypass pipe is smaller than or equal to the width of a gap between the screw and the material barrel, the bypass pipe is fixedly connected with the material barrel, and the bypass pipe is located at the downstream position of the input hole. And a vibration exciter is mounted on the peripheral surface of the bypass pipe. The vibration exciter can enable the high polymer material in the charging barrel to indirectly vibrate, so that the molten high polymer material and the supercritical fluid can be fully and uniformly mixed.

Description

Technical Field

[0001] The present application relates to the field of plastic extrusion molding technology, and in particular to a supercritical fluid-assisted polymer material extrusion molding machine. Background Art

[0002] Supercritical refers to the state of a substance when the pressure and temperature exceed its critical pressure and critical temperature at the same time. The substance in the supercritical state has high compressibility and its density is close to that of ordinary liquids, so it has good performance in dissolving other substances.

[0003] Critical foaming molding is a process in which supercritical carbon dioxide or nitrogen or other gases are first injected into the plasticizing device during the injection molding, extrusion and blow molding processes to allow the gas to be fully and evenly mixed / diffused with the molten raw materials to form a single-phase mixed sol. The sol is then introduced into the mold cavity or extrusion die to cause a large pressure drop in the sol, thereby causing the gas to precipitate and form a large number of bubble nuclei. In the subsequent cooling and molding process, the bubble nuclei inside the sol continue to grow and form, and ultimately a microporous foamed plastic product is obtained.

[0004] The basic process of supercritical fluid microporous plastic extrusion molding is: polymer material pellets or powder enter the barrel of the extruder from the hopper mouth for plasticization, and at the same time, the supercritical fluid stored in the gas cylinder is pumped into the barrel by the high-pressure plunger pump. The supercritical fluid is mixed with the melt in the barrel to finally form a supercritical fluid / molten polymer material single-phase system. The single-phase system induces bubble nucleation by causing thermodynamic instability through the sudden drop in pressure of the extruder head. The temperature of the extruder head is controlled to solidify the bubbles and obtain microporous foam products. The continuous extrusion molding cycle of microporous plastics is short and the production efficiency is high, which is suitable for the industrial production of microporous plastics.

[0005] However, due to the short residence time of the molten material in the extruder barrel, it is difficult to fully and evenly mix the molten polymer material and the supercritical fluid. Also, due to the complexity of the microcellular plastic extrusion molding process, the products obtained by microcellular plastic extrusion molding often have uneven cell sizes and unstable cell density. Summary of the invention

[0006] In order to fully and evenly mix the supercritical fluid injected into the barrel with the plastic melt which has a very short residence time in the barrel, to form a single-phase system of supercritical fluid / molten polymer material with a high gas content, and to obtain microporous plastic with high pore density and uniform size, the present application provides a supercritical fluid-assisted polymer material extrusion molding machine.

[0007] The supercritical fluid-assisted polymer material extrusion molding machine provided in this application adopts the following technical solution: A supercritical fluid-assisted polymer material extrusion molding machine includes a molding unit and a supercritical fluid supply unit, wherein the molding unit includes a barrel, a screw and a driving mechanism, wherein the driving mechanism is used to drive the screw to rotate in the barrel; the barrel is provided with a supercritical fluid input hole, wherein the input hole is used for the supercritical fluid supply unit to inject supercritical fluid; the barrel is provided with a bypass pipe, wherein both ends of the bypass pipe are respectively fixedly connected to the barrel and are connected to the inner cavity of the barrel at the same time, wherein the bypass pipe is a thin-walled metal pipe, wherein the inner diameter of the bypass pipe is less than or equal to the gap width between the screw and the barrel, wherein the bypass pipe is located downstream of the input hole, and an exciter is installed on the outer peripheral surface of the bypass pipe.

[0008] By adopting the above technical solution, the driving mechanism drives the screw to rotate so that the screw pushes the molten polymer material in the barrel. In this process, the supercritical fluid supply unit inputs the supercritical fluid into the barrel from the input hole to mix the supercritical fluid with the polymer material. When the mixture of the polymer material and the supercritical fluid passes through the bypass pipe, part of the polymer material enters the bypass pipe and then enters the barrel through the bypass pipe. In the process of the molten polymer material flowing through the bypass pipe, the vibrator vibrates the polymer material in the bypass pipe through the wall of the bypass pipe, thereby indirectly vibrating the polymer material in the barrel, so that the molten polymer material and the supercritical fluid can be fully and evenly mixed, and the pore density distribution is stable. The bypass pipe is set as a thin-walled metal pipe, so that the bypass pipe is easier to vibrate under the drive of the vibrator. Since the polymer material in the bypass pipe and the polymer material in the barrel are continuous, the vibrator can indirectly vibrate the polymer material in the barrel. The vibrator does not need to directly vibrate the screw or barrel, which can reduce the vibration effect of the vibrator on the screw and barrel, which is beneficial to reduce the dynamic friction between the screw and the barrel and is beneficial to protecting the screw and the barrel.

[0009] Optionally, both ends of the bypass pipe are respectively provided with a flexible sleeve, the flexible sleeve is provided with an inner flange, and the two ends of the bypass pipe are respectively provided with an outer flange, the outer flange is used to prevent the flexible sleeve from detaching from the bypass pipe, a buffer pad is provided between the inner flange of the flexible sleeve and the corresponding outer flange, and the flexible sleeve is provided with an internal thread; the barrel is provided with two connecting pipes, the connecting pipes are provided with external threads matching the internal threads, and the two connecting pipes are respectively connected to the two flexible sleeves; a metal O-ring is provided on the inner side of the flexible sleeve, the metal O-ring is located between the outer flange and the end face of the connecting pipe away from the barrel, and an annular groove is provided on the end face of the connecting pipe away from the barrel or the end face of the outer flange close to the barrel, and the annular groove is used to accommodate the metal O-ring.

[0010] By adopting the above technical solution, the two ends of the bypass pipe are detachably connected to the two joint pipes through the union sleeves, respectively, so that the bypass pipe can be easily disassembled and cleaned. When the union sleeve is connected to the joint pipe, the union sleeve and the joint pipe are spirally locked, so that the end face of the joint pipe and the outer flange jointly extrude the metal O-ring, so that the metal O-ring plays a sealing role on the connection position between the joint pipe and the bypass pipe. The metal O-ring is made of metal, which is not easy to fail at the high temperature of the molten polymer material, and is not easy to merge with the molten polymer material. On the other hand, the two sides of the outer flange of the bypass pipe are buffered by the metal O-ring and the buffer pad respectively, so that the vibration of the bypass pipe is not easily transmitted to the joint pipe, which is conducive to further reducing the vibration effect of the exciter on the barrel.

[0011] Optionally, the buffer pad is a spring washer.

[0012] By adopting the above technical solution, the spring gasket can play an anti-loosening role on the connection between the flexible sleeve and the joint pipe, thereby reducing the loosening of the connection part between the flexible sleeve and the joint pipe under the vibration of the exciter.

[0013] Optionally, the joint pipe is provided with a vibration isolator, and the vibration isolator is used to connect to an external fixing component.

[0014] By adopting the above technical solution, the vibration isolation component is fixedly connected to the external structure, and the vibration isolation component can play a reinforcing role on the joint pipe to further reduce the vibration effect of the exciter on the joint pipe and the barrel.

[0015] Optionally, the vibration isolation component includes a fixed connecting rod and a fixed connecting member, the fixed connecting member includes a first clamping plate and a second clamping plate, the first clamping plate and the second clamping plate are detachably connected, the first clamping plate and the second clamping plate jointly clamp the joint pipe, and the fixed connecting rod is fixedly connected to a side of the first clamping plate away from the second clamping plate.

[0016] By adopting the above technical solution, the fixed connection piece of the vibration isolation piece is detachably connected to the joint pipe, so that the barrel of the molding unit can be separated from the vibration isolation piece, making the molding unit easy to disassemble and assemble.

[0017] Optionally, the exciter is connected to the bypass pipe via a mounting base, the mounting base includes a first clip and a second clip, the first clip and the second clip are detachably connected, the first clip and the second clip jointly clamp the bypass pipe, and the exciter is fixedly mounted on a side of the first clip away from the second clip.

[0018] By adopting the above technical solution, the vibrator is fixed on the first clip of the mounting seat, and the first clip and the second clip of the mounting seat are detachably connected, so that the mounting seat can be detachably mounted on the bypass pipe, making the disassembly and assembly of the vibrator more convenient.

[0019] Optionally, the bypass pipe is coated with a heat insulation layer.

[0020] By adopting the above technical solution, the bypass pipe is insulated from the outside world by the heat insulation layer, which can reduce the heat loss of the bypass pipe and ensure the fluidity of the molten polymer material in the bypass pipe.

[0021] Optionally, both ends of the bypass pipe are tangentially connected to the barrel, and the two ends of the bypass pipe are staggered with each other along the length direction of the barrel and are respectively located on both sides of the center line of the bypass pipe, and the direction of the pipe mouth of the bypass pipe is tangentially adapted to the rotation speed of the screw.

[0022] By adopting the above technical solution, the directions of the two ports of the bypass pipe are tangentially adapted to the rotation speed of the screw, so that the molten polymer material can enter and exit the bypass pipe more easily.

[0023] Optionally, the screw sleeve is provided with a spiral compensation sleeve, which is fixedly connected to the screw, the volume of the material of the spiral compensation sleeve is greater than or equal to the volume of the bypass pipe, and the axial position of the spiral compensation sleeve corresponds to the feed port position of the bypass pipe.

[0024] By adopting the above technical solution, the polymer material in the barrel enters the bypass pipe, causing the density of the material in the barrel to change. By arranging a spiral compensation sleeve at a position on the screw corresponding to the inlet of the bypass pipe, the space occupied by the spiral compensation sleeve is used to compensate for the volume change caused by the reduction of the polymer material, so that the density of the material in the barrel is generally more balanced.

[0025] Optionally, the spiral compensation sleeve includes a plurality of arc plates, which are connected in sequence along the spiral direction of the screw rod, the arc angle of the arc plates is between 180 degrees and 200 degrees, and the arc plates are fitted on the screw rod by screws.

[0026] By adopting the above technical solution, the arc plates are connected in sequence to form a spiral compensation sleeve, and the arc plates are fixed on the screw rod by screws. The arc angle of the arc plates is between 180 degrees and 200 degrees, so that the arc plates can form a holding effect on the screw rod.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: When the molten polymer material flows through the bypass pipe, the vibrator vibrates the polymer material in the bypass pipe through the wall of the bypass pipe, thereby indirectly vibrating the polymer material in the barrel, so that the molten polymer material and the supercritical fluid can be fully and evenly mixed, and the pore density distribution is stable.

[0028] The vibration isolator is fixedly connected to the external structure, and the vibration isolator can play a reinforcing role on the joint pipe to further reduce the vibration effect of the exciter on the joint pipe and the barrel. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of this embodiment.

[0030] Figure 2 This is a side view of the embodiment used to illustrate the connection relationship between the bypass pipe and the barrel.

[0031] Figure 3 It is a cross-sectional view of this embodiment for illustrating the connection relationship between the bypass pipe and the joint pipe.

[0032] Figure 4 yes Figure 3 Magnified view at A in the middle.

[0033] Figure 5 It is a schematic diagram of the present embodiment for reflecting the installation state of the spiral compensation sleeve.

[0034] Description of reference numerals: 10. Molding unit; 1. Barrel; 11. Input hole; 12. Bypass pipe; 121. External flange; 13. Union sleeve; 131. Internal thread; 132. Internal flange; 14. Connector pipe; 141. External thread; 142. Annular groove; 15. Buffer pad; 16. Metal O-ring; 17. Vibration isolator; 171. Fixed connecting rod; 172. Fixed connecting piece; 1721. First clamping plate; 172 2. Second clamping plate; 18. Insulation layer; 181. Inner layer of insulation cotton; 182. Outer layer of spiral sheath; 2. Screw; 21. Spiral compensation sleeve; 211. Arc plate; 3. Hopper; 4. Heater; 6. Driving mechanism; 5. Vibrator; 51. Mounting seat; 511. First clamping piece; 512. Second clamping piece; 20. Supercritical fluid supply unit; 7. Gas storage bottle; 8. High-pressure plunger pump; 9. Gas injection connector. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-5 This application is described in further detail.

[0036] The present application embodiment discloses a supercritical fluid assisted polymer material extrusion molding machine. Figure 1The supercritical fluid-assisted polymer material extrusion molding machine includes a molding unit 10 and a supercritical fluid supply unit 20. The supercritical fluid supply unit 20 includes a gas storage bottle 7, a high-pressure plunger pump 8 and a gas injection joint 9. The high-pressure plunger pump 8 is connected to the gas storage bottle 7 and the gas injection joint 9 through a pipeline. The high-pressure plunger pump 8 pumps the supercritical fluid in the gas storage bottle 7 into the barrel 1 through the gas injection joint 9.

[0037] The molding unit 10 includes a barrel 1, a screw 2, a hopper 3, a heater 4 and a driving mechanism 6. The hopper 3 is connected to the inner cavity of the barrel 1, the heater 4 is installed on the outer surface of the barrel 1, and the driving mechanism 6 is an electric motor with a reducer. The driving mechanism 6 is used to drive the screw 2 to rotate in the barrel 1 so that the screw 2 pushes the molten polymer material in the barrel 1 to the front end of the barrel 1; the barrel 1 is provided with a supercritical fluid input hole 11, and the input hole 11 is used for the supercritical fluid supply unit 20 to inject supercritical fluid.

[0038] The barrel 1 is provided with a bypass pipe 12, both ends of which are fixedly connected to the barrel 1 respectively and connected to the inner cavity of the barrel 1 at the same time. The bypass pipe 12 is a thin-walled metal pipe. The bypass pipe 12 is located downstream of the input hole 11, that is, the bypass pipe 12 is close to the outlet end of the barrel 1 relative to the input hole 11. An exciter 5 is installed on the outer peripheral surface of the bypass pipe 12. The exciter 5 is a vibration motor or an ultrasonic generator. The exciter 5 is close to the outlet end of the bypass pipe 12.

[0039] The driving mechanism 6 drives the screw 2 to rotate, so that the screw 2 pushes the molten polymer material in the barrel 1 forward. In this process, the supercritical fluid supply unit 20 inputs the supercritical fluid into the barrel 1 from the input hole 11, so that the supercritical fluid is mixed with the polymer material. When the mixture of the polymer material and the supercritical fluid passes through the bypass pipe 12, part of the polymer material enters the bypass pipe 12, and then enters the barrel 1 through the bypass pipe 12. In the process of the molten polymer material flowing through the bypass pipe 12, the vibrator 5 vibrates the polymer material in the bypass pipe 12 through the pipe wall of the bypass pipe 12, and then indirectly vibrates the polymer material in the barrel 1, so that the molten polymer material and the supercritical fluid can be fully and evenly mixed, so that the pore density distribution is stable, and it can adapt to the preparation of thin and fine structure foaming materials, for example, it can make the pore density in the foaming yarn more uniform.

[0040] Reference Figure 2 and Figure 3 The two ends of the bypass pipe 12 are tangentially connected to the barrel 1. The two ends of the bypass pipe 12 are staggered with each other along the length direction of the barrel 1 and are respectively located on both sides of the center line of the bypass pipe 12. The direction of the pipe mouth of the bypass pipe 12 is tangentially adapted to the rotation speed of the screw 2.

[0041] In this embodiment, the inner diameter of the bypass pipe 12 is smaller than the variation range of the gap width between the screw 2 and the barrel 1 , and the gap width between the screw 2 and the barrel 1 refers to the single-side width of the annular gap between the screw 2 and the barrel 1 .

[0042] Reference Figure 3 and Figure 4 , the two ends of the bypass pipe 12 are respectively sleeved with a union sleeve 13, and the union sleeve 13 is provided with an internal thread 131; the union sleeve 13 is provided with an inner flange 132, and the two ends of the bypass pipe 12 are respectively provided with an outer flange 121, the inner diameter of the inner flange 132 is larger than the outer diameter of the bypass pipe 12, and smaller than the outer diameter of the outer flange 121, and the outer flange 121 is used to prevent the union sleeve 13 from being separated from the bypass pipe 12, and a buffer pad 15 is provided between the inner flange 132 of the union sleeve 13 and the corresponding outer flange 121, and the buffer pad 15 is a spring gasket, which can specifically be a disc spring gasket or a corrugated spring gasket, etc. The spring gasket can also be replaced by a rubber gasket, a silicone gasket or a cork gasket, etc.

[0043] The barrel 1 is provided with two joint pipes 14, and the joint pipes 14 are provided with external threads 141 adapted to the internal threads 131. The two joint pipes 14 are respectively connected to the two union sleeves 13; a metal O-ring 16 is provided on the inner side of the union sleeve 13, and the metal O-ring 16 is located between the outer flange 121 and the end face of the joint pipe 14 away from the barrel 1; the end face of the joint pipe 14 away from the barrel 1 or the end face of the outer flange 121 close to the barrel 1 is provided with an annular groove 142, and the annular groove 142 is used to accommodate the metal O-ring 16.

[0044] Reference Figure 2 and Figure 3 The joint pipe 14 is provided with a vibration isolation member 17, which is a steel member. The vibration isolation member 17 includes a fixed connecting rod 171 and a fixed connecting member 172. The fixed connecting member 172 includes a first clamping plate 1721 and a second clamping plate 1722. The first clamping plate 1721 and the second clamping plate 1722 are detachably connected by a bolt and nut assembly. The first clamping plate 1721 and the second clamping plate 1722 jointly clamp the joint pipe 14. The fixed connecting rod 171 is welded and fixed to the side of the first clamping plate 1721 away from the second clamping plate 1722. The fixed connecting rod 171 is used to connect an external fixed component, such as a frame of an extrusion molding machine or a building structure adjacent to the extrusion molding machine.

[0045] Reference Figure 3 The vibrator 5 is connected to the bypass pipe 12 via a mounting base 51. The mounting base 51 includes a first clip 511 and a second clip 512. The first clip 511 and the second clip 512 are detachably connected via a bolt and nut assembly. The first clip 511 and the second clip 512 clamp the bypass pipe 12 together. The vibrator 5 is fixedly mounted on a side of the first clip 511 away from the second clip 512.

[0046] Reference Figure 4 The bypass pipe 12 is covered with an insulation layer 18, and the insulation layer 18 includes an insulation cotton inner layer 181 and a spiral sheath outer layer 182. The insulation cotton covers the outer peripheral surface of the bypass pipe 12. The insulation cotton material of the insulation cotton inner layer 181 is glass wool or rock wool, etc. The insulation cotton material is wrapped and covered with a spiral sheath to form a layered structure. The spiral sheath covering the insulation cotton material serves as the spiral sheath outer layer 182, and the spiral sheath is tied and fixed with a cable tie or steel wire.

[0047] Reference Figure 5 The screw 2 is provided with a spiral compensation sleeve 21, which includes a plurality of arc plates 211, which are connected in sequence along the spiral direction of the screw 2. The arc angle of the arc plates 211 is between 180 and 200 degrees. The number of the arc plates 211 is set according to the multiple of the pitch of the bypass pipe 12 across the screw 2, and the arc plates 211 are fitted on the screw 2 by screws. The volume of the material of the spiral compensation sleeve 21 is greater than or equal to the volume of the bypass pipe 12, and the position of the spiral compensation sleeve 21 in the axial direction of the screw 2 is located between the two ends of the bypass pipe 12. By arranging the spiral compensation sleeve 21 at the position corresponding to the feed port of the bypass pipe 12 on the screw 2, the space occupied by the spiral compensation sleeve 21 is used to compensate for the volume change caused by the reduction of the polymer material, so that the density of the material in the barrel 1 is generally more balanced.

[0048] The implementation principle of the supercritical fluid-assisted polymer material extrusion molding machine of the embodiment of the present application is as follows: the bypass pipe 12 is set as a thin-walled metal pipe, so that the bypass pipe 12 is easier to vibrate under the drive of the vibrator 5, so that the bypass pipe 12 indirectly vibrates the polymer material in the barrel 1. The vibrator 5 does not need to directly vibrate the screw 2 or the barrel 1, which can reduce the vibration effect of the vibrator 5 on the screw and the barrel 1, which is beneficial to reduce the dynamic friction between the screw 2 and the barrel 1, and is beneficial to protect the screw 2 and the barrel 1.

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. Supercritical fluid assisted polymer material extrusion molding machine, characterized by: The invention comprises a molding unit (10) and a supercritical fluid supply unit (20), wherein the molding unit (10) comprises a barrel (1), a screw (2) and a driving mechanism (6), wherein the driving mechanism (6) is used to drive the screw (2) to rotate in the barrel (1); the barrel (1) is provided with a supercritical fluid input hole (11), wherein the input hole (11) is used for the supercritical fluid supply unit (20) to inject supercritical fluid; the barrel (1) is provided with a bypass pipe (12), wherein both ends of the bypass pipe (12) are respectively fixedly connected to the barrel (1) and are connected to the inner cavity of the barrel (1); the bypass pipe (12) is a thin-walled metal pipe, wherein the inner diameter of the bypass pipe (12) is less than or equal to the gap width between the screw (2) and the barrel (1); the bypass pipe (12) is located downstream of the input hole (11), and an exciter (5) is installed on the outer peripheral surface of the bypass pipe (12).

2. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 1, characterized in that: Both ends of the bypass pipe (12) are respectively sleeved with a slewing sleeve (13), the slewing sleeve (13) is provided with an inner flange (132), and both ends of the bypass pipe (12) are respectively provided with an outer flange (121), the outer flange (121) is used to prevent the slewing sleeve (13) from detaching from the bypass pipe (12), a buffer pad (15) is provided between the inner flange (132) of the slewing sleeve (13) and the corresponding outer flange (121), and the slewing sleeve (13) is provided with an internal thread (131); the barrel (1) is provided with two joint pipes (14), and the joint pipe (14) is provided with a thread connected to the The internal thread (131) is adapted to the external thread (141), and the two joint pipes (14) are respectively connected to the two union sleeves (13); a metal O-ring (16) is provided on the inner side of the union sleeve (13), and the metal O-ring (16) is located between the outer flange (121) and the end face of the joint pipe (14) away from the barrel (1); the end face of the joint pipe (14) away from the barrel (1) or the end face of the outer flange (121) close to the barrel (1) is provided with an annular groove (142), and the annular groove (142) is used to accommodate the metal O-ring (16).

3. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 2, characterized in that: The buffer pad (15) is a spring pad.

4. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 2, characterized in that: The joint pipe (14) is provided with a vibration isolator (17), and the vibration isolator (17) is used to connect an external fixing component.

5. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 4, characterized in that: The vibration isolation member (17) comprises a fixed connecting rod (171) and a fixed connecting member (172); the fixed connecting member (172) comprises a first clamping plate (1721) and a second clamping plate (1722); the first clamping plate (1721) and the second clamping plate (1722) are detachably connected; the first clamping plate (1721) and the second clamping plate (1722) jointly clamp the joint pipe (14); and the fixed connecting rod (171) is fixedly connected to a side of the first clamping plate (1721) away from the second clamping plate (1722).

6. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 1, characterized in that: The exciter (5) and the bypass pipe (12) are connected via a mounting seat (51); the mounting seat (51) comprises a first clamp (511) and a second clamp (512); the first clamp (511) and the second clamp (512) are detachably connected; the first clamp (511) and the second clamp (512) jointly clamp the bypass pipe (12); and the exciter (5) is fixedly mounted on a side of the first clamp (511) away from the second clamp (512).

7. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 1, characterized in that: The bypass pipe (12) is coated with a heat insulation layer (18).

8. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 1, characterized in that: The two ends of the bypass pipe (12) are tangentially connected to the barrel (1), the two ends of the bypass pipe (12) are staggered along the length direction of the barrel (1), and are respectively located on both sides of the center line of the bypass pipe (12), and the direction of the pipe mouth of the bypass pipe (12) is tangentially adapted to the rotation speed of the screw (2).

9. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 1, characterized in that: The screw rod (2) is provided with a spiral compensation sleeve (21), the spiral compensation sleeve (21) is fixedly connected to the screw rod (2), the volume of the material of the spiral compensation sleeve (21) is greater than or equal to the volume of the bypass pipe (12), and the spiral compensation sleeve (21) is located between the two ends of the bypass pipe (12) in the axial direction of the screw rod (2).

10. The supercritical fluid-assisted polymer material extrusion molding machine according to claim 9, characterized in that: The spiral compensation sleeve (21) comprises a plurality of arc-shaped plates (211), the arc-shaped plates (211) being connected in sequence along the spiral direction of the screw rod (2), the arc angle of the arc-shaped plates (211) being between 180 degrees and 200 degrees, and the arc-shaped plates (211) being fitted and mounted on the screw rod (2) by means of screws.

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