Water-cooled film blowing machine

Abstract

This invention discloses a water-cooled blown film machine, belonging to the technical field of blown film machines. The invention includes a frame, with an extrusion die mechanism mounted on the top of the frame. Below the extrusion die mechanism is a blown film mechanism, and below the blown film mechanism is a herringbone plate mechanism. A winding mechanism is located on the left side of the herringbone plate mechanism. The herringbone plate mechanism includes a frame body fixedly mounted on the frame, with herringbone clamps symmetrically mounted on the frame body. Electric push rods are symmetrically fixedly mounted on the frame body, and sliders are fixedly mounted at the output ends of the electric push rods. A rotating shaft is rotatably mounted between the two sliders. A waste film winding roller is fixedly mounted on the outer side of the rotating shaft, and an adsorption mechanism for fixing the film is provided on the waste film winding roller. This water-cooled blown film machine can automatically cut and recycle waste generated at the herringbone plate extrusion point, improving equipment maintenance efficiency and ensuring a high waste recycling rate.

Description

Technical Field

[0001] This invention relates to the field of blown film machine technology, specifically a water-cooled blown film machine. Background Technology

[0002] A blown film machine is a core piece of equipment that extrudes molten plastic through an extruder and then through a ring die to form a tubular film bubble. After cooling and shaping, traction, edge trimming, and winding, it is made into a plastic film. It is widely used in food packaging, medical packaging, industrial packaging and other fields. Water-cooled blown film machines mostly adopt a downward blowing structure with the die facing downward. After the molten material is extruded from the die, it forms a downward-extending film bubble. The film bubble is rapidly cooled and shaped by a cooling water ring. Then, it is flattened by a herringbone plate, pulled by traction rollers, and the edge trimming device removes the material on both sides before being wound into a finished film.

[0003] The prior art (Chinese patent publication number: CN121083903A, publication date: 2025-12-09) discloses a plastic container bag blown film machine, including a blown film mechanism, a film body auxiliary pressure mechanism disposed within the blown film mechanism, a film diameter adjustment mechanism disposed within the film body auxiliary pressure mechanism, and a film support mechanism disposed within the film body auxiliary pressure mechanism; the blown film mechanism is used to cooperate with an extruder to blown film molten plastic particles; the film body auxiliary pressure mechanism includes a pressure-bearing base and an anti-detachment pad disposed at the bottom of the pressure-bearing base. By adding a film diameter adjustment mechanism and a film support mechanism inside the existing blown film machine, when the molten masterbatch passes through the blown film machine and is drawn upward, the upwardly extending film support mechanism, in conjunction with the flow guide, guides the outwardly expanding part of the bottom of the container bag, preventing the container bag from wrinkling or deforming inward due to environmental factors and interference from high-pressure airflow. The prior art (Chinese patent publication number: CN212266677U, publication date: 2021-01-01) discloses a blown film machine with a waste cutting and recycling device, including a first conveying pipe, a feed funnel fixedly connected to the top of one side of the first conveying pipe, a waste feed inlet opened at the top of the other side of the first conveying pipe, a crusher at the top of the waste feed inlet, a second rotating shaft inside the first conveying pipe, both ends of the second rotating shaft being rotatably connected to the first conveying pipe through bearings, a first spiral blade fixedly connected to the outside of the second rotating shaft, the end of the second rotating shaft away from the crusher passing through the first conveying pipe, a gearbox being provided at the end of the first conveying pipe near the feed funnel, and one end of the second rotating shaft being drively connected to the output end of the gearbox. This blown film machine with a waste cutting and recycling device solves the problems of inconvenient adjustment of cutting spacing and low waste transportation efficiency of existing blown film machines with waste cutting and recycling devices.

[0004] During the use of existing blown film machines, the film material is easily damaged due to friction or unstable air pressure during the extrusion process of the herringbone plate. Existing equipment lacks the function of recycling damaged film material, which often requires manual stopping of the machine and cutting and removing the damaged material, making the operation difficult and presenting certain defects in use. Summary of the Invention

[0005] The purpose of this invention is to provide a water-cooled blown film machine to solve the problems mentioned in the background art. In the current blown film machines on the market, the film material is easily damaged due to friction or unstable air pressure during the extrusion of the film material by the herringbone plate. Existing equipment lacks the function of recycling damaged film material, and often requires manual stopping of the machine to cut and remove the damaged material, which is difficult to operate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a water-cooled blown film machine, comprising a frame, an extrusion die mechanism mounted on the top of the frame, a blown film mechanism disposed below the extrusion die mechanism, and a herringbone plate mechanism disposed below the blown film mechanism. A winding mechanism is disposed on the left side of the herringbone plate mechanism. The herringbone plate mechanism includes a frame fixedly mounted on the frame, with herringbone clamps symmetrically mounted on the frame. Electric push rods are symmetrically fixedly mounted on the frame, and sliders are fixedly mounted at the output ends of the electric push rods. A rotating shaft is mounted between the blocks. A waste take-up roller is fixedly mounted on the outside of the rotating shaft. An adsorption mechanism for fixing the film is provided on the waste take-up roller. A first film-cutting assembly is provided on the outside of the waste take-up roller. A film-splitting assembly for cutting waste is provided on the inside of the waste take-up roller. An air pump for pneumatically controlling the film-splitting assembly is provided on the frame. A second film-cutting assembly for cutting and pressing the film is provided on the herringbone clamp. After the first film-cutting assembly completes the cutting, the second film-cutting assembly is driven by a transmission mechanism to cut the film.

[0007] Preferably, during the movement of the slider driven by the electric push rod, the waste material take-up roller is controlled to adhere to the film below the damaged area of ​​the film. After the waste material take-up roller adheres to and adsorbs the film, the first film cutting assembly cuts the film below the damaged area of ​​the film. The waste material take-up roller is driven by a motor to take up the damaged film.

[0008] Preferably, the first film cutting assembly includes a first cutter fixedly mounted on the frame, a blade holder rotatably mounted on the outer side of the rotating shaft, and a second cutter fixedly mounted on the upper end of the blade holder. The second cutter is slidably mounted on the frame, and during the sliding process, the second cutter cooperates with the first cutter to cut the film.

[0009] Preferably, the adsorption mechanism includes an air supply pipe connected to an air pump, and the air supply pipe is rotatably connected to a rotating shaft. An air passage and a first air hole are opened at the right end of the rotating shaft near the air supply pipe. The first air hole communicates with the inner cavity of the waste material winding roller. A sealing slide is slidably installed on the inner side of the waste material winding roller, and the sliding sealing sleeve of the sealing slide is fitted on the outer side of the rotating shaft. A sealing stretching membrane is sealed between the sealing slide and the inner wall of the end of the waste material winding roller. A spring is connected between the inner wall of the end of the waste material winding roller and the sealing slide. During the air pumping process, the sealing slide slides along the inner wall of the waste material winding roller under negative pressure.

[0010] Preferably, the adsorption mechanism includes adsorption holes evenly opened on the outer wall of the waste winding roller, a second air hole is opened on the arc surface of the sealing slide that fits the rotating shaft, and the second air hole and the first air hole are connected during the sliding of the sealing slide close to the air supply pipe, a connecting hole is opened on the sealing slide, and the second air hole and the adsorption hole are connected through the connecting hole, and the adsorption hole adsorbs the membrane under negative pressure.

[0011] Preferably, the film separating assembly includes a slitting blade uniformly and fixedly installed on the outside of the sealing slide, and the slitting blade slides through the adsorption hole, and the sealing slide drives the slitting blade to slit the waste material wound on the outside of the waste material take-up roller during the elastic reset process.

[0012] Preferably, the second film cutting assembly includes a rotating frame elastically rotatably mounted on the outer side of the top of two herringbone clamps, and a telescopic frame elastically telescopically mounted on the rotating frame via a spring, and a pressing roller rotatably mounted on the top of the telescopic frame. At the same time, during the rotation of the rotating frame on the two herringbone clamps, the film above the damaged area is pressed by the two pressing rollers.

[0013] Preferably, the second film cutting assembly includes a third cutter fixedly mounted on a rotating frame, and the third cutter cuts the film above the damaged area as the two rotating frames rotate closer together.

[0014] Preferably, the transmission mechanism includes a guide rod fixedly installed on the frame, and a lifting plate is mounted on the guide rod. A cable is fixedly installed on the upper surface of the lifting plate. The upper end of the cable is wound around the shaft of the rotating frame. During the downward movement of the lifting plate, the rotating frame is rotated by pulling the cable. A first permanent magnet is fixedly installed on the lower surface of the lifting plate, and a second permanent magnet is fixedly installed on the upper surface of the second cutter. During the sliding of the second cutter, the lifting plate is attracted to move downward by the magnetic force of the first and second permanent magnets.

[0015] Compared with the prior art, the beneficial effects of the present invention are: the water-cooled blown film machine can automatically cut and recycle the waste generated at the herringbone plate extrusion point, which improves the equipment's fault maintenance efficiency and ensures the recycling rate of waste. The specific details are as follows; 1. Equipped with an adsorption mechanism and a first film cutting assembly, when a breakage is detected during the film extrusion process, the electric push rod is controlled to move the waste material take-up roller to fit against the rear section of the film at the breakage point. At the same time, the adsorption holes on the waste material take-up roller can adsorb and position the film. Subsequently, the first cutter moves with the waste material take-up roller and can cooperate with the second cutter to cut the lower end of the film at the breakage point. Finally, the waste material take-up roller is controlled to rotate, which can automatically rewind the broken film.

[0016] 2. A second film-cutting assembly is provided. As the first cutter slides, the second permanent magnet on it moves to the area below the lifting plate, causing the lifting plate to move downward under the magnetic force of the first and second permanent magnets. This, in turn, pulls the rotating frame at the top of the herringbone clamping plate to rotate via a cable. At this time, the pressing rollers on the two telescopic frames will approach each other and squeeze the upper section of the damaged film, achieving film compression and preventing the inner side of the normal film from losing pressure and becoming damaged. At the same time, the third cutter on the rotating frame can cut the upper end of the damaged film, making it easier for the waste winding roller to wind up and recycle the entire damaged film.

[0017] 3. Equipped with a waste take-up roller, a sealing slide, and a slitting blade, when air is drawn from the air supply pipe, the sealing slide slides along the inside of the waste take-up roller under air pressure, and then moves to the outside of the film body, ensuring that the cutting edge of the slitting blade on the sealing slide faces the side of the film body. After the film body is finished being rolled up, the sealing slide is controlled to slide back to its original position, allowing the slitting blade on the sealing slide to cut the damaged film body after winding. The cut film body then naturally peels off on the outside of the waste take-up roller, eliminating the need for manual collection and facilitating subsequent recycling and reuse. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the main structure of the present invention; Figure 3 This is a schematic diagram of the herringbone clamp installation structure of the present invention; Figure 4 This is a schematic diagram of the waste material take-up roller installation structure of the present invention; Figure 5 For the present invention Figure 4 Enlarged structural diagram at point A in the middle; Figure 6 This is a schematic diagram of the mounting structure of the first and second cutters of the present invention; Figure 7 This is a schematic diagram of the installation structure of the waste material take-up roller and the second cutter of the present invention; Figure 8 This is a schematic cross-sectional view of the waste material take-up roller of the present invention; Figure 9 This is a schematic diagram of the sealing slide installation structure of the present invention; Figure 10 This is a schematic diagram of the lifting plate installation structure of the present invention; Figure 11 This is a schematic diagram of the pressing roller installation structure of the present invention.

[0019] In the diagram: 1. Frame; 2. Extrusion die mechanism; 3. Blown film mechanism; 4. Herringbone plate mechanism; 5. Rewinding mechanism; 6. Frame body; 7. Herringbone clamp; 8. Electric push rod; 9. Slider; 10. Rotating shaft; 11. Waste rewinding roller; 12. First cutter; 13. Blade holder; 14. Second cutter; 15. Air pump; 16. Air supply pipe; 17. Air passage; 18. First air hole; 19. Sealing slide; 20. Sealing telescopic membrane; 21. Second air hole; 22. Connecting hole; 23. Adsorption hole; 24. Slitting blade; 25. Guide rod; 26. Lifting plate; 27. First permanent magnet; 28. Second permanent magnet; 29. ​​Cable; 30. Rotating frame; 31. Telescopic frame; 32. Pressing roller; 33. Third cutter. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: In the operation of existing blown film machines, the film material is easily damaged due to friction or unstable air pressure during the extrusion process by the herringbone plate. Existing equipment lacks a function to recover damaged film material, often requiring manual stopping and cutting / removing, which is difficult. To solve this technical problem, this example discloses the following technical content. Please refer to [link / reference]. Figures 1-6As shown; a water-cooled blown film machine includes a frame 1, an extrusion die mechanism 2 mounted on the top of the frame 1, a blown film mechanism 3 disposed below the extrusion die mechanism 2, and a herringbone plate mechanism 4 disposed below the blown film mechanism 3. A winding mechanism 5 is disposed on the left side of the herringbone plate mechanism 4. The herringbone plate mechanism 4 includes a frame body 6 fixedly mounted on the frame 1, with herringbone clamps 7 symmetrically mounted on the frame body 6. Electric push rods 8 are symmetrically fixedly mounted on the frame body 6, and a slider 9 is fixedly mounted at the output end of the electric push rod 8. A rotating shaft 10 is rotatably mounted between the two sliders 9. A waste take-up roller 11 is fixedly mounted on the outside of the rotating shaft 10. An adsorption mechanism for fixing the film body is provided on the waste take-up roller 11. A first film cutting assembly is provided on the outside of the waste take-up roller 11. An air pump 15 for pneumatically controlling the film separating assembly is provided on the frame 6. A second film cutting assembly for cutting and pressing the film body is provided on the herringbone clamp 7. After the first film cutting assembly completes the cutting, the second film cutting assembly is driven by the transmission mechanism to cut the film body.

[0022] During the movement of the slider 9 driven by the electric push rod 8, the waste take-up roller 11 is controlled to adhere to the film below the damaged area. After the waste take-up roller 11 adheres to and adsorbs the film, the first film cutting assembly cuts the film below the damaged area. The waste take-up roller 11 is driven by a motor to take up the damaged film. The first film cutting assembly includes a first cutter 12 fixedly installed on the frame 6, and a knife holder 13 is rotatably installed on the outside of the rotating shaft 10. A second cutter 14 is fixedly installed on the upper end of the knife holder 13. At the same time, the second cutter 14 is slidably installed on the frame 6. During the sliding process, the second cutter 14 cooperates with the first cutter 12 to cut the film.

[0023] The adsorption mechanism includes an air supply pipe 16 connected to the air pump 15, and the air supply pipe 16 is rotatably connected to the rotating shaft 10. The rotating shaft 10 has an air passage 17 and a first air hole 18 at the right end near the air supply pipe 16. The first air hole 18 is connected to the inner cavity of the waste material winding roller 11. A sealing slide plate 19 is slidably installed on the inner side of the waste material winding roller 11. The sliding sealing sleeve of the sealing slide plate 19 is fitted on the outer side of the rotating shaft 10. A sealing stretching membrane 20 is sealed between the sealing slide plate 19 and the inner wall of the end of the waste material winding roller 11. A spring is connected between the inner wall of the end of the waste material winding roller 11 and the sealing slide plate 19. During the air pump 15's air extraction process, the sealing slide plate 19 slides along the inner wall of the waste material winding roller 11 under negative pressure. The adsorption mechanism includes adsorption holes 23 evenly opened on the outer wall of the waste winding roller 11, and a second air hole 21 opened on the arc surface of the sealing slide 19 that fits against the rotating shaft 10. During the process of the sealing slide 19 sliding close to the air supply pipe 16, the second air hole 21 and the first air hole 18 are connected. A connecting hole 22 is opened on the sealing slide 19, and the second air hole 21 and the adsorption hole 23 are connected through the connecting hole 22. The adsorption hole 23 adsorbs the membrane under negative pressure.

[0024] The extrusion die mechanism 2 can hot-melt the raw material into the blown film mechanism 3. After the blown film is cooled, it is conveyed to the herringbone plate mechanism 4 for extrusion and then wound up by the winding mechanism 5. When damage is detected during the film extrusion process, photoelectric sensors, pressure sensors, and visual inspection can be used to control the electric push rod 8 to push the slider 9 to slide on the frame 6, which will drive the waste material winding roller 11 to move and fit against the rear section of the damaged film. At the same time, the air pump 15 is controlled to draw air through the air supply pipe 16. At this time, the air supply pipe 16 draws air from the inside of the sealing stretch film 20 through the air passage 17 and the first air hole 18 on the rotating shaft 10. The gas causes the sealing slide 19 to slide inside the waste winding roller 11. When the second air hole 21 and the first air hole 18 on the waste winding roller 11 are connected, the air supply pipe 16 will draw air from the inside of the cavity of the waste winding roller 11 through the second air hole 21 and the connecting hole 22, so that the adsorption hole 23 on the waste winding roller 11 can adsorb and position the film. Then, the first cutter 12 moves with the waste winding roller 11 and can cooperate with the second cutter 14 to cut the lower end of the damaged film. Then, the motor is controlled to drive the waste winding roller 11 to rotate, so that the damaged film can be automatically wound up.

[0025] like Figures 10-11 As shown, the second film cutting assembly includes a rotating frame 30 that is elastically rotatably mounted on the outer side of the top of two herringbone clamps 7. A telescopic frame 31 is elastically telescopically mounted on the rotating frame 30 via a spring. A pressing roller 32 is rotatably mounted on the top of the telescopic frame 31. During the rotation of the rotating frame 30 on the two herringbone clamps 7, the two pressing rollers 32 press the film above the damaged area. The second film cutting assembly includes a third cutter 33 that is fixedly mounted on the rotating frame 30. During the rotation of the two rotating frames 30 toward each other, the third cutter 33 cuts the film above the damaged area. The transmission mechanism includes a guide rod 25 fixedly installed on the frame 6, and a lifting plate 26 is lifted and lowered on the guide rod 25. A cable 29 is fixedly installed on the upper surface of the lifting plate 26. The upper end of the cable 29 is wound around the shaft of the rotating frame 30. During the downward movement of the lifting plate 26, the rotating frame 30 is rotated by pulling the cable 29. A first permanent magnet 27 is fixedly installed on the lower surface of the lifting plate 26, and a second permanent magnet 28 is fixedly installed on the upper surface of the second cutter 14. During the sliding of the second cutter 14, the lifting plate 26 is attracted to move downward by the magnetic force of the first permanent magnet 27 and the second permanent magnet 28.

[0026] As the first cutter 12 slides, the second permanent magnet 28 on it moves to the lower part of the lifting plate 26, causing the lifting plate 26 to move downward under the magnetic force of the first permanent magnet 27 and the second permanent magnet 28. Then, the cable 29 pulls the rotating frame 30 at the upper end of the herringbone clamp 7 to rotate. At this time, the pressing rollers 32 on the two telescopic frames 31 will approach each other and squeeze the upper part of the damaged membrane to achieve membrane pressing, avoiding the loss of pressure and damage to the inner side of the normal membrane in the upper part. At the same time, the third cutter 33 on the two rotating frames 30 approach each other to cut the upper part of the damaged membrane, making it easier for the waste winding roller 11 to wind up and recycle the entire damaged membrane.

[0027] Example 2: The technical content disclosed in this example is a further improvement based on Example 1. Existing blown film machines are inconvenient for collecting cutting waste, requiring periodic cleaning of the waste rewinding structure. To further solve this technical problem, this example discloses the following technical content, such as... Figures 7-9 As shown, a film-splitting assembly for cutting waste is provided on the inner side of the waste take-up roller 11. The film-splitting assembly includes a slitting blade 24 that is uniformly fixed on the outer side of the sealing slide plate 19. The slitting blade 24 slides through the adsorption hole 23, and the sealing slide plate 19 drives the slitting blade 24 to cut the waste wound on the outer side of the waste take-up roller 11 during the elastic reset process.

[0028] When the air supply pipe 16 draws air, the sealing slide 19 slides along the inside of the waste winding roller 11 under the action of air pressure, and then moves to the outside of the film body, ensuring that the cutting edge of the slitting blade 24 on the sealing slide 19 faces the side of the film body. After the film body is wound up, the sealing slide 19 is controlled to slide back to its original position, so that the slitting blade 24 on the sealing slide 19 can cut the damaged film body after winding, so that the cut film body peels off on the outside of the waste winding roller 11 without the need for manual subsequent collection, which facilitates subsequent recycling and reuse.

[0029] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0030] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A water-cooled blown film machine, comprising a frame (1), wherein an extrusion die mechanism (2) is installed on the top of the frame (1), and a blown film mechanism (3) is provided below the extrusion die mechanism (2), and a herringbone plate mechanism (4) is provided below the blown film mechanism (3), and a winding mechanism (5) is provided on the left side of the herringbone plate mechanism (4). Its features are, The herringbone plate mechanism (4) includes a frame (6) fixedly installed on the frame (1), and herringbone clamps (7) are symmetrically installed on the frame (6). Electric push rods (8) are symmetrically fixedly installed on the frame (6), and sliders (9) are fixedly installed at the output end of the electric push rods (8). A rotating shaft (10) is rotatably installed between the two sliders (9). A waste take-up roller (11) is fixedly installed on the outside of the rotating shaft (10), and an adsorption mechanism for fixing the film is provided on the waste take-up roller (11). A first film cutting assembly is provided on the outside of the waste take-up roller (11), and a film splitting assembly for splitting waste is provided on the inside of the waste take-up roller (11). An air pump (15) for pneumatically controlling the film splitting assembly is provided on the frame (6). A second film cutting assembly for cutting and pressing the film is provided on the herringbone clamps (7), and the second film cutting assembly is driven by the transmission mechanism to cut the film after the first film cutting assembly completes the cutting. The adsorption mechanism includes an air supply pipe (16) connected to an air pump (15), and the air supply pipe (16) and the rotating shaft (10) are rotatably connected. An air passage (17) and a first air hole (18) are opened at the right end of the rotating shaft (10) near the air supply pipe (16). The first air hole (18) is connected to the inner cavity of the waste winding roller (11). A sealing slide plate (19) is slidably installed on the inner side of the waste winding roller (11). The sliding sealing sleeve of the sealing slide plate (19) is fitted on the outer side of the rotating shaft (10). A sealing stretching membrane (20) is sealed between the sealing slide plate (19) and the inner wall of the end of the waste winding roller (11). A spring is connected between the inner wall of the end of the waste winding roller (11) and the sealing slide plate (19). During the air pump (15) pumping air, the sealing slide plate (19) slides along the inner wall of the waste winding roller (11) under negative pressure. The adsorption mechanism includes adsorption holes (23) evenly opened on the outer wall of the waste winding roller (11), and a second air hole (21) is opened on the arc surface of the sealing slide (19) that fits against the rotating shaft (10). During the process of the sealing slide (19) sliding close to the air supply pipe (16), the second air hole (21) and the first air hole (18) are connected. A connecting hole (22) is opened on the sealing slide (19), and the second air hole (21) and the adsorption hole (23) are connected through the connecting hole (22). The adsorption hole (23) adsorbs the membrane under negative pressure. The film-splitting assembly includes a slitting blade (24) uniformly fixedly installed on the outside of the sealing slide (19), and the slitting blade (24) slides through the adsorption hole (23), and the sealing slide (19) drives the slitting blade (24) to slit the waste material wound on the outside of the waste material take-up roller (11) during the elastic reset process.

2. The water-cooled blown film machine according to claim 1, characterized in that: During the process of the electric push rod (8) pushing the slider (9) to move, the waste material take-up roller (11) is controlled to adhere to the film below the damaged area of ​​the film. After the waste material take-up roller (11) adheres to the adsorbed film, the first film cutting assembly cuts the film below the damaged area of ​​the film. The waste material take-up roller (11) is driven by the motor to take up the damaged film.

3. A water-cooled blown film machine according to claim 1, characterized in that: The first film cutting assembly includes a first cutter (12) fixedly mounted on the frame (6), and a knife holder (13) rotatably mounted on the outside of the rotating shaft (10). A second cutter (14) is fixedly mounted on the upper end of the knife holder (13). The second cutter (14) is slidably mounted on the frame (6). During the sliding process, the second cutter (14) cooperates with the first cutter (12) to cut the film.

4. A water-cooled blown film machine according to claim 1, characterized in that: The second film cutting assembly includes a rotating frame (30) elastically rotatably mounted on the outer side of the top of two herringbone clamps (7), and a telescopic frame (31) elastically telescopically mounted on the rotating frame (30) by a spring, and a pressing roller (32) rotatably mounted on the top of the telescopic frame (31). At the same time, the rotating frame (30) on the two herringbone clamps (7) presses the film above the damaged area through the two pressing rollers (32) during the rotation process.

5. A water-cooled blown film machine according to claim 4, characterized in that: The second film cutting assembly includes a third cutter (33) fixedly mounted on a rotating frame (30), and the third cutter (33) cuts the film above the damaged area as the two rotating frames (30) rotate and approach each other.

6. A water-cooled blown film machine according to claim 3, characterized in that: The transmission mechanism includes a guide rod (25) fixedly installed on the frame (6), and a lifting plate (26) is installed on the guide rod (25). A cable (29) is fixedly installed on the upper surface of the lifting plate (26). The upper end of the cable (29) is wound around the shaft of the rotating frame (30). During the downward movement of the lifting plate (26), the rotating frame (30) is rotated by the cable (29). A first permanent magnet (27) is fixedly installed on the lower surface of the lifting plate (26), and a second permanent magnet (28) is fixedly installed on the upper surface of the second cutter (14). During the sliding process of the second cutter (14), the lifting plate (26) is attracted to move downward by the magnetic force of the first permanent magnet (27) and the second permanent magnet (28).

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