Bending machine for polypropylene plate processing

Abstract

The invention relates to the field of polypropylene plate processing, in particular to a bending machine for polypropylene plate processing, which comprises a flat plate and a rotating plate, one ends of a high-temperature air duct and a cooling air duct far away from an air bellow intersect and are fixedly connected with a mixed air duct, and the mixed air duct is fixedly connected with a U-shaped air duct. The end, away from the mixed air duct, of the U-shaped air duct is turned upwards and fixedly connected with a forked air duct, the upper end of the forked air duct is fixedly connected with an upper air duct, the lower end of the forked air duct is fixedly connected with a lower air duct, and linkage adjusting devices are installed on the two sides of a gap between the flat plate and the rotating plate. The linkage adjusting device adjusts the air inlet amount of the high-temperature air duct and the air inlet amount of the cooling air duct in a linkage mode according to the rotating angle of the first rotating arm, and the temperature of a polypropylene plate can be kept within a suitable bending range in the whole bending process; and the bending efficiency of the polypropylene plate is improved while the plate is prevented from cracking.

Description

Technical Field

[0001] This invention relates to the field of polypropylene sheet processing, and more specifically to a bending machine for processing polypropylene sheets. Background Technology

[0002] Existing polypropylene sheet bending machines typically use electric heating or hot air heating at the bending point to soften the polypropylene sheet before bending. However, the hot air temperature blown out by these machines is usually fixed. When the hot air temperature remains constant, the surface temperature of the polypropylene sheet is directly proportional to the heating time. Once the bending point of the polypropylene sheet is heated to a suitable bending temperature, if the hot air continues to heat it during the subsequent bending process, it may cause the polypropylene sheet to overheat, resulting in excessive softening, uneven deformation, or scorching. If heating is stopped during the bending process, the polypropylene sheet may cool and solidify too quickly, leading to uneven bending or cracks. Therefore, existing polypropylene sheet bending machines struggle to maintain a suitable temperature during the polypropylene sheet bending process. Furthermore, existing polypropylene sheet bending machines typically use natural cooling after bending, but this natural cooling is slow and significantly reduces the bending efficiency of the polypropylene sheet. If cold air is introduced for rapid cooling after bending, it will cause thermal stress concentration in the polypropylene sheet, which may lead to cracks, warping, or deformation. Therefore, existing polypropylene sheet bending machines have difficulty controlling the cooling temperature, resulting in the polypropylene sheet cooling too slowly or too quickly, which affects the quality of the cooled polypropylene sheet.

[0003] Therefore, it is necessary to invent a bending machine for processing polypropylene sheets. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a bending machine for processing polypropylene sheets, comprising a flat plate and a rotating plate, wherein a first rotating arm is fixedly installed on both sides of the flat plate near the rotating plate, and a second rotating arm is fixedly installed on both sides of the rotating plate near the flat plate; the first rotating arm and the second rotating arm are rotatably connected; the top surface of the flat plate and the rotating plate is used to place the polypropylene sheet; a wind box is provided below the rotating plate; the wind box contains upper and lower air chambers; one end of the upper air chamber is fixedly connected to a high-temperature air duct, and one end of the lower air chamber is fixedly connected to a cooling air duct; the ends of the high-temperature air duct and the cooling air duct away from the wind box intersect and are fixedly connected. A mixing air duct is fixedly connected to a U-shaped air duct. The end of the U-shaped air duct away from the mixing air duct is folded upward and fixedly connected to a branching air duct. The two ends of the branching air duct away from the U-shaped air duct extend to the upper and lower sides of the plate, respectively. The upper end of the branching air duct is fixedly connected to an upper air duct, which is directly above the gap between the plate and the rotating plate. The lower end of the branching air duct is fixedly connected to a lower air duct, which is directly below the gap between the plate and the rotating plate. A linkage adjustment device is installed on both sides of the gap between the plate and the rotating plate. The linkage adjustment device is used to adjust and distribute the air intake of the high-temperature air duct and the cooling air duct into the mixing air duct according to the rotation angle of the first rotating arm.

[0005] Preferably, a filter screen is fixedly installed on the inner wall of the upper and lower air chambers of the air box at the end away from the high-temperature air duct and the cooling air duct, and a fan is fixedly installed on the inner wall of the upper and lower air chambers of the air box, with the fan positioned between the filter screen and the high-temperature air duct or the cooling air duct.

[0006] Preferably, an electric heating tube is fixedly installed in the upper air chamber of the air box, a power supply is installed on one side of the outer wall of the air box, and the electric heating tube is electrically connected to the power supply. A cooling tube is fixedly installed in the lower air chamber of the air box, a condenser is provided on one side of the cooling air duct, coolant is injected into the cooling tube, and both ends of the cooling tube pass through the air box and are fixedly connected to the condenser.

[0007] Preferably, the linkage adjustment device includes a partition plate, one end of which is fixedly connected to a rotating rod. The rotating rod is rotatably installed at the intersection of the inner walls of the high-temperature air duct and the cooling air duct. The partition plate can rotate to close the high-temperature air duct or the cooling air duct. Both ends of the rotating rod pass through the high-temperature air duct and the cooling air duct and extend to both sides.

[0008] Preferably, the linkage adjustment device includes a bracket, which is fixedly installed at the bottom of the cooling air duct. Both ends of the bracket extend to the sides and bend upward to the rotatable connection between the first rotating arm and the second rotating arm. The upwardly bent part of the bracket is a hollow structure.

[0009] Preferably, one end of the shaft that is rotatably connected to the second rotating arm extends outward and is inserted into the upper end of the bent portion on the bracket. A first gear is fixedly installed on the shaft extending outward from the second rotating arm. The two ends of the rotating rod are respectively inserted into the lower part of the two ends bent upward on the bracket. A second gear is fixedly installed on both ends of the rotating rod. A transmission toothed belt is sleeved between the outer walls of the first gear and the second gear.

[0010] Preferably, a motor is fixedly installed at the upper end of the bent portion of the bracket, and the output end of the motor is fixedly connected to the rotating shaft extending outward from the second rotating arm. The motor can drive the second rotating arm to rotate the rotating plate.

[0011] Preferably, a frame plate is fixedly installed at the end of the flat plate away from the rotating plate, the bottom surface of the frame plate is set on the ground, and the bifurcated air duct and the U-shaped air duct are both embedded in the frame plate.

[0012] Preferably, a corrugated pipe is fixedly installed at the end of the downdraft duct away from the branch duct, and the side of the corrugated pipe away from the downdraft duct is fixedly bonded to the side of the flat plate and the rotating plate that are close to each other. The corrugated pipe can deflect as the rotating plate rotates.

[0013] Preferably, both sides of the top surface of the flat plate and the rotating plate are provided with buckles for fixing the polypropylene plate, and hinges are fixedly installed on both sides of the end of the flat plate and the rotating plate that are close to each other, and the hinges can deflect as the rotating plate rotates.

[0014] The beneficial effects of this invention are as follows: The linkage adjustment device adjusts the air intake of the high-temperature air duct and the cooling air duct into the mixed air duct according to the rotation angle of the first rotating arm. The polypropylene plate is fixed to the top surface of the flat plate and the rotating plate. When the angle between the flat plate and the rotating plate is 180°, the linkage adjustment device closes the cooling air duct. The hot air in the high-temperature air duct is delivered to the branched air duct and blown out through the upper and lower air ducts to heat the polypropylene plate. After the bent part of the polypropylene plate is completely heated and softened, the rotating plate is driven to rotate, causing the polypropylene plate to bend. During the bending process, the linkage adjustment device gradually opens the cooling air duct while gradually closing the high-temperature air duct, causing the temperature of the hot air blown out of the upper and lower air ducts to gradually decrease. When the angle between the flat plate and the rotating plate is 180°, the cooling air duct is closed. When the included angle is 90°, the linkage adjustment device completely closes the high-temperature air duct. The cold air in the cooling air duct is delivered to the branched air duct and blown out through the upper and lower air ducts, accelerating the cooling and molding of the polypropylene sheet. This helps maintain the temperature of the polypropylene sheet within a suitable bending range throughout the bending process. On the one hand, it avoids overheating of the polypropylene sheet, which could lead to excessive softening, uneven deformation, or scorching of the material. On the other hand, it avoids the polypropylene sheet cooling and solidifying too quickly, which could lead to uneven bending or cracks. This invention can also gradually reduce the temperature of the cooling fan, preventing the polypropylene sheet temperature from dropping too quickly and causing thermal stress concentration. This avoids cracks, warping, or deformation of the sheet while accelerating the overall cooling speed, which is beneficial to improving the bending efficiency of the polypropylene sheet. Attached Figure Description

[0015] Figure 1 A front view of a bending machine for processing polypropylene sheets provided by the present invention; Figure 2 A bending diagram of a bending machine for processing polypropylene sheets provided by the present invention; Figure 3 A side view of a bending machine for processing polypropylene sheets provided by the present invention; Figure 4 A side cross-sectional view of a bending machine for processing polypropylene sheets provided by the present invention; Figure 5 A schematic diagram of the internal structure of the bellows of a bending machine for processing polypropylene sheets provided by the present invention; Figure 6 A schematic diagram of the linkage adjustment device for a bending machine for processing polypropylene sheets provided by the present invention; Figure 7 Exploded view of a linkage adjustment device for a bending machine for processing polypropylene sheets provided by the present invention; Figure 8 Detailed view of the corrugated pipe and hinge of a bending machine for processing polypropylene sheets provided by the present invention. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Example

[0017] like Figure 1 - Figure 4As shown, a bending machine for processing polypropylene sheets according to a first aspect embodiment of the present invention includes a flat plate 11 and a rotating plate 12. First rotating arms 14 are fixedly installed on both sides of the flat plate 11 near the rotating plate 12, and second rotating arms 15 are fixedly installed on both sides of the rotating plate 12 near the flat plate 11. The first rotating arms 14 and the second rotating arms 15 are rotatably connected. The top surfaces of the flat plate 11 and the rotating plate 12 are used to place polypropylene sheets. A wind box 31 is provided below the rotating plate 12. The wind box 31 contains two air chambers, upper and lower. One end of the upper air chamber of the wind box 31 is fixedly connected to a high-temperature air duct 28, and one end of the lower air chamber of the wind box 31 is fixedly connected to a cooling air duct 29. The ends of the high-temperature air duct 28 and the cooling air duct 29 away from the wind box 31 intersect and are fixedly connected to a mixing air duct 27. The mixing air duct 27 is fixedly connected to the U-shaped air duct 26. The end of the U-shaped air duct 26 away from the mixing air duct 27 is folded upward and fixedly connected to the branch air duct 22. The two ends of the branch air duct 22 away from the U-shaped air duct 26 extend to the upper and lower sides of the plate 11 respectively. The upper end of the branch air duct 22 is fixedly connected to the upper air duct 23, which is directly above the gap between the plate 11 and the rotating plate 12. The lower end of the branch air duct 22 is fixedly connected to the lower air duct 24, which is directly below the gap between the plate 11 and the rotating plate 12. Linkage adjustment devices are installed on both sides of the gap between the plate 11 and the rotating plate 12. The linkage adjustment devices are used to adjust and distribute the air intake of the high temperature air duct 28 and the cooling air duct 29 into the mixing air duct 27 according to the rotation angle of the first rotating arm 14.

[0018] In the above embodiments, it should be noted that the upper air chamber of the air box 31 can deliver hot air into the high-temperature air duct 28, and the lower air chamber of the air box 31 can deliver cold air into the cooling air duct 29. The air in the high-temperature air duct 28 and the cooling air duct 29 will be mixed in the mixing air duct 27 and introduced into the branching air duct 22 through the U-shaped air duct 26. The polypropylene plate is fixed on the top surface of the flat plate 11 and the rotating plate 12. When the included angle between the flat plate 11 and the rotating plate 12 is 180°, the cooling air duct 29 is closed by the linkage adjustment device. The hot air in the high-temperature air duct 28 is delivered to the branching air duct 22 and blown out of the heated polypropylene plate through the upper air duct 23 and the lower air duct 24. After the bent part of the polypropylene plate is completely heated and softened, the rotating plate 12 is driven to rotate. The rotating plate 11 drives the polypropylene sheet to bend. During the bending process, the linkage adjustment device gradually opens the cooling air duct 29 while gradually closing the high-temperature air duct 28. This causes the temperature of the hot air blown out of the upper air duct 23 and the lower air duct 24 to gradually decrease, maintaining the temperature of the polypropylene sheet within a suitable bending range throughout the bending process. This prevents the polypropylene sheet from overheating, which could lead to excessive softening, uneven deformation, or scorching of the material. When the angle between the flat plate 11 and the rotating plate 12 reaches 90°, the polypropylene sheet is fully bent. At this point, the high-temperature air duct 28 is completely closed by the linkage adjustment device. The cold air in the cooling air duct 29 is then transported to the branch air duct 22 and blown out through the upper air duct 23 and the lower air duct 24, accelerating the cooling and molding of the polypropylene sheet. This prevents the polypropylene sheet from cooling and solidifying too quickly, which could lead to uneven bending or cracks. Furthermore, it gradually reduces the temperature of the cooling fan, preventing the polypropylene sheet from cooling down too quickly and causing thermal stress concentration. This prevents the sheet from cracking, warping, or deforming while accelerating the overall cooling speed, thus improving the bending efficiency of the polypropylene sheet. Example

[0019] like Figure 2 - Figure 5 As shown, a bending machine for processing polypropylene sheets includes all the contents of Example 1. In addition, a filter screen 32 is fixedly installed on the inner wall of the upper and lower air chambers of the air box 31 at the end away from the high-temperature air duct 28 and the cooling air duct 29. A fan 33 is fixedly installed on the inner wall of the upper and lower air chambers of the air box 31. The fan 33 is located between the filter screen 32 and the high-temperature air duct 28 or the cooling air duct 29. An electric heating tube 34 is fixedly installed in the upper air chamber of the air box 31. A power supply is installed on one side of the outer wall of the air box 31. The electric heating tube 34 is electrically connected to the power supply. A cooling tube 35 is fixedly installed in the lower air chamber of the air box 31. A condenser 36 is provided on one side of the cooling air duct 29. Coolant is injected into the cooling tube 35. Both ends of the cooling tube 35 pass through the air box 31 and are fixedly connected to the condenser 36.

[0020] In the above embodiments, it should be noted that starting the fan 33 can draw outside air into the air box 31 and deliver it into the high-temperature air duct 28 and the cooling air duct 29. The filter screen 32 can effectively isolate external dust. The electric heating tube 34 can be energized and generate heat, which can heat the air in the upper air chamber of the air box 31. The condenser 36 can exchange the coolant in the cooling pipe 35 and cool the air in the lower air chamber of the hot air box 31. By starting the electric heating tube 34, it is beneficial to cooperate with the fan 33 to deliver hot air into the high-temperature air duct 28. By starting the condenser 36, it is beneficial to cooperate with the fan 33 to deliver cold air into the cooling air duct 29. Example

[0021] like Figure 1 - Figure 4 and Figure 6 , Figure 7 As shown, a bending machine for processing polypropylene sheets includes all the contents of Example 2. Furthermore, the linkage adjustment device includes a partition 45, one end of which is fixedly connected to a rotating rod 44. The rotating rod 44 is rotatably installed at the intersection of the inner walls of the high-temperature air duct 28 and the cooling air duct 29. The partition 45 can rotatably close either the high-temperature air duct 28 or the cooling air duct 29. Both ends of the rotating rod 44 penetrate the high-temperature air duct 28 and the cooling air duct 29 and extend to both sides. The linkage adjustment device includes a bracket 16, which is fixedly installed at the bottom of the cooling air duct 29. Both ends of the bracket 16 extend to both sides and bend upwards to the rotatable connection between the first rotating arm 14 and the second rotating arm 15. The upward bending portion of the bracket 16... The device has a hollow structure. One end of the shaft that is rotatably connected to the first rotating arm 14 extends outward and is inserted into the upper end of the bent part of the bracket 16. The shaft extending outward from the second rotating arm 15 is fixedly mounted with the first gear 41. The two ends of the rotating rod 44 are respectively inserted into the lower part of the two ends of the upward bend of the bracket 16. The two ends of the rotating rod 44 are fixedly mounted with the second gear 43. A transmission toothed belt 42 is sleeved between the outer walls of the first gear 41 and the second gear 43. The upper end of the bent part of the bracket 16 is fixedly mounted with the motor 17. The output end of the motor 17 is fixedly connected to the shaft extending outward from the second rotating arm 15. The motor 17 can drive the second rotating arm 15 to rotate the rotating plate 12.

[0022] In the above embodiment, it should be noted that in the initial state, the included angle between the plate 11 and the rotating plate 12 is 180° and the partition 45 closes the cooling air duct 29. The second rotating arm 15 is driven by the starting motor 17 to rotate the rotating plate 12, so as to achieve the effect of bending the polypropylene plate. During the rotation of the second rotating arm 15, the first gear 41 is driven to rotate. The first gear 41 drives the second gear 43 through the toothed belt 42. The second gear 43 drives the rotating rod 44 to rotate, which is conducive to gradually opening the cooling air duct 29 of the partition 45 and gradually closing the high temperature air duct 28. Example

[0023] like Figure 1 , Figure 2 . Figure 7 and Figure 8 As shown, a bending machine for processing polypropylene sheets includes all the contents of Example 3. In addition, a frame plate 21 is fixedly installed at the end of the flat plate 11 away from the rotating plate 12. The bottom surface of the frame plate 21 is set on the ground. The bifurcated air duct 22 and the U-shaped air duct 26 are both embedded in the frame plate 21. A corrugated pipe 25 is fixedly installed at the end of the lower air duct 24 away from the bifurcated air duct 22. The side of the corrugated pipe 25 away from the lower air duct 24 is fixedly bonded to the side of the flat plate 11 and the rotating plate 12 that are close to each other. The corrugated pipe 25 can deflect as the rotating plate 12 rotates. Buckles for fixing polypropylene sheets are provided on both sides of the top surface of the flat plate 11 and the rotating plate 12. Hinges 13 are fixedly installed on both sides of the end of the flat plate 11 and the rotating plate 12 that are close to each other. The hinges 13 can deflect as the rotating plate 12 rotates.

[0024] In the above embodiments, it should be noted that the frame plate 21 has the function of supporting the branched air duct 22 and the U-shaped air duct 26. The corrugated pipe 25 is made of heat-resistant plastic. The air blown out of the lower air duct 24 can be guided by the corrugated pipe 25 so that it can always act on the bending part of the polypropylene plate. The hinge 13 can enhance the stability and strength of the plate 11 and the rotating plate 12 during rotation.

[0025] The usage process of this invention is as follows: Those skilled in the art fix the polypropylene plate to the top surface of the flat plate 11 and the rotating plate 12. At this time, the partition 45 closes the cooling air duct 29. The electric heating tube 34 and the fan 33 are activated to deliver hot air into the high-temperature air duct 28. Simultaneously, the condenser 36 and the fan 33 are activated to deliver cold air into the cooling air duct 29. The hot air in the high-temperature air duct 28 is delivered to the branching air duct 22 and blown out through the upper air duct 23 and the lower air duct 24, heating the polypropylene plate. After the bent part of the polypropylene plate is completely heated and softened, the motor 17 is activated to drive the second rotating arm 15 to rotate the rotating plate 12, causing the polypropylene plate to bend. During the bending process of the polypropylene plate... The second rotating arm 15 drives the first gear 41 to rotate. The first gear 41 drives the second gear 43 through the toothed belt 42. The second gear 43 drives the rotating rod 44 to rotate, which drives the partition 45 to gradually open the cooling air duct 29 and at the same time gradually close the high temperature air duct 28, so that the temperature of the hot air blown out of the upper air duct 23 and the lower air duct 24 gradually decreases. When the included angle between the plate 11 and the rotating plate 12 rotates to 90°, the polypropylene plate is completely bent. At this time, the partition 45 completely closes the high temperature air duct 28. The cold air in the cooling air duct 29 is delivered to the branch air duct 22 and blown out through the upper air duct 23 and the lower air duct 24, which accelerates the cooling and molding of the polypropylene plate.

[0026] The above description is merely a preferred embodiment of the present invention. Any person skilled in the art can modify the present invention or modify it into an equivalent technical solution using the technical solutions described above. Therefore, any simple modifications or equivalent substitutions made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A bending machine for processing polypropylene sheets, comprising a flat plate (11) and a rotating plate (12), wherein a first rotating arm (14) is fixedly installed on both sides of one end of the flat plate (11) near the rotating plate (12), and a second rotating arm (15) is fixedly installed on both sides of one end of the rotating plate (12) near the flat plate (11), wherein the first rotating arm (14) and the second rotating arm (15) are rotatably connected, and the top surface of the flat plate (11) and the rotating plate (12) is used to place polypropylene sheets, characterized in that: Below the rotating plate (12) is a wind box (31), and inside the wind box (31) are two air chambers, one upper and one lower. One end of the upper air chamber of the wind box (31) is fixedly connected to a high-temperature air duct (28), and one end of the lower air chamber of the wind box (31) is fixedly connected to a cooling air duct (29). The ends of the high-temperature air duct (28) and the cooling air duct (29) away from the wind box (31) intersect and are fixedly connected to a mixing air duct (27). The mixing air duct (27) is fixedly connected to a U-shaped air duct (26). The end of the U-shaped air duct (26) away from the mixing air duct (27) is folded upward and fixedly connected to a branching air duct (22). The branching air duct (22) is away from the U-shaped air duct (27). 6) The two ends extend to the upper and lower sides of the plate (11) respectively. The upper end of the branched air duct (22) is fixedly connected to the upper air duct (23). The upper air duct (23) is directly above the gap between the plate (11) and the rotating plate (12). The lower end of the branched air duct (22) is fixedly connected to the lower air duct (24). The lower air duct (24) is directly below the gap between the plate (11) and the rotating plate (12). Linkage adjustment devices are installed on both sides of the gap between the plate (11) and the rotating plate (12). The linkage adjustment devices are used to adjust and distribute the air intake of the high temperature air duct (28) and the cooling air duct (29) into the mixing air duct (27) according to the rotation angle of the first rotating arm (14).

2. The bending machine for processing polypropylene sheets according to claim 1, characterized in that: A filter screen (32) is fixedly installed on one end of the inner wall of the upper and lower air chambers of the air box (31) away from the high temperature air duct (28) and the cooling air duct (29). A fan (33) is fixedly installed on the inner wall of the upper and lower air chambers of the air box (31). The fan (33) is located between the filter screen (32) and the high temperature air duct (28) or the cooling air duct (29).

3. A bending machine for processing polypropylene sheets according to claim 2, characterized in that: An electric heating tube (34) is fixedly installed in the upper air chamber of the air box (31). A power supply is installed on one side of the outer wall of the air box (31). The electric heating tube (34) is electrically connected to the power supply. A cooling tube (35) is fixedly installed in the lower air chamber of the air box (31). A condenser (36) is provided on one side of the cooling air duct (29). Coolant is injected into the cooling tube (35). Both ends of the cooling tube (35) pass through the air box (31) and are fixedly connected to the condenser (36).

4. The bending machine for processing polypropylene sheets according to claim 1, characterized in that: The linkage adjustment device includes a partition (45), one end of which is fixedly connected to a rotating rod (44). The rotating rod (44) is rotatably installed at the intersection of the inner walls of the high-temperature air duct (28) and the cooling air duct (29). The partition (45) can rotate to close the high-temperature air duct (28) or the cooling air duct (29). Both ends of the rotating rod (44) pass through the high-temperature air duct (28) and the cooling air duct (29) and extend to both sides.

5. A bending machine for processing polypropylene sheets according to claim 4, characterized in that: The linkage adjustment device includes a bracket (16), which is fixedly installed at the bottom of the cooling air duct (29). The two ends of the bracket (16) extend to both sides and bend upward to the rotatable connection between the first rotating arm (14) and the second rotating arm (15). The upwardly bent part of the bracket (16) is a hollow structure.

6. A bending machine for processing polypropylene sheets according to claim 5, characterized in that: One end of the shaft that is rotatably connected to the second rotating arm (15) extends outward and is inserted into the upper end of the bent part on the bracket (16). The shaft extending outward from the second rotating arm (15) is fixedly installed with the first gear (41). The two ends of the rotating rod (44) are respectively inserted into the lower part of the two ends of the bracket (16) bent upward. The two ends of the rotating rod (44) are fixedly installed with the second gear (43). A transmission toothed belt (42) is sleeved between the outer walls of the first gear (41) and the second gear (43).

7. A bending machine for processing polypropylene sheets according to claim 6, characterized in that: A motor (17) is fixedly installed on the upper end of the bent part of the bracket (16). The output end of the motor (17) is fixedly connected to the rotating shaft extending outward from the second rotating arm (15). The motor (17) can drive the second rotating arm (15) to rotate the rotating plate (12).

8. A bending machine for processing polypropylene sheets according to claim 1, characterized in that: A frame plate (21) is fixedly installed at the end of the flat plate (11) away from the rotating plate (12). The bottom surface of the frame plate (21) is set on the ground. The bifurcated air duct (22) and the U-shaped air duct (26) are both embedded in the frame plate (21).

9. A bending machine for processing polypropylene sheets according to claim 1, characterized in that: A corrugated pipe (25) is fixedly installed at the end of the downdraft duct (24) away from the branch duct (22). The side of the corrugated pipe (25) away from the downdraft duct (24) is fixedly bonded to the side of the plate (11) and the rotating plate (12) that are close to each other. The corrugated pipe (25) can deflect as the rotating plate (12) rotates.

10. A bending machine for processing polypropylene sheets according to claim 1, characterized in that: Both sides of the top surface of the plate (11) and the rotating plate (12) are provided with buckles for fixing polypropylene plates. Hinges (13) are fixedly installed on both sides of the end of the plate (11) and the rotating plate (12) that are close to each other. The hinges (13) can deflect as the rotating plate (12) rotates.

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