Low-stress FPC (Flexible Printed Circuit) laminating device

Abstract

The utility model discloses a low-stress FPC (Flexible Printed Circuit) film laminating device, which comprises a rack provided with a conveyor belt; the film supply assembly is located above the conveying belt and connected to the rack, the film supply assembly comprises an unwinding roller, a guide roller and an electrostatic neutralizer, and the electrostatic neutralizer is located on one side of the guide roller; the pressing assembly is located above the conveying belt and connected to the rack, the pressing assembly comprises a pressing roller, an infrared heater, a pressing fan and guide rollers, the infrared heater, the pressing roller and the pressing fan are sequentially arranged in the conveying direction, the pressing roller is used for being matched with the conveying belt to press a protective film on the surface of the FPC body, and the guide rollers are all located above the pressing roller; the protective film wound on the guide roller and the pressing roller is inclined to the horizontal plane, and the working end of the static neutralizer directly faces the area between the pressing roller and the guide roller. According to the film laminating device, the film laminating resistance can be reduced, the film laminating tightness is high, comprehensive and reliable extrusion fitting can be realized, the film laminating effect is uniform and reliable, and the film laminating action is reliable.

Description

Technical Field

[0001] This utility model relates to the field of FPC processing, and in particular to a low-stress FPC coating device. Background Technology

[0002] FPC (Flexible Printed Circuit), also known as flexible circuit board, is a type of printed circuit board with high reliability and excellent flexibility, made from polyimide or polyester film as the substrate. It is widely used in consumer electronics, automotive electronics, medical devices and other fields.

[0003] FPC coating equipment is a specialized device for pressing a protective film or reinforcing plate onto the surface of an FPC substrate. It typically uses a roller pressing method to achieve the covering and pressing of the protective film. During the pressing process, bubbles or wrinkles can easily form between the protective film and the surface of the FPC substrate due to impurities or stress, resulting in poor coating effect and a decline in the quality of the FPC product. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a low-stress FPC coating device, which can reduce coating resistance, improve the overall coating adhesion, and achieve high coating reliability.

[0005] A low-stress FPC coating device according to an embodiment of the present invention includes:

[0006] The frame is equipped with a conveyor belt, which drives the FPC body forward along the conveying direction.

[0007] The film supply assembly is located above the conveyor belt and connected to the frame. The film supply assembly includes an unwinding roller, a guide roller, and an electrostatic neutralizer. The unwinding roller is used to unwind the protective film, and the electrostatic neutralizer is located on one side of the guide roller.

[0008] The pressing assembly, located above the conveyor belt and connected to the frame, includes a pressure roller, an infrared heater, and a pressing fan. The guide roller, infrared heater, pressure roller, and pressing fan are arranged sequentially along the conveying direction. The pressure roller is used to press the protective film onto the surface of the FPC body in conjunction with the conveyor belt. The guide rollers are all located above the horizontal position of the pressure roller so that the protective film wrapped around the guide roller and the pressure roller is inclined to the horizontal plane. The working end of the electrostatic neutralizer faces the area between the pressure roller and the guide roller, and the working end of the pressing fan faces the conveyor belt.

[0009] In this embodiment, the electrostatic neutralizer includes an ion fan and an air filter. The air outlet of the ion fan is directly opposite the area between the pressure roller and the guide roller, and the air filter is located at the air inlet of the ion fan.

[0010] In this embodiment, the central axis of the ion fan's outlet is parallel to the horizontal plane, and the ion fan is located below the guide roller on the side away from the pressure roller.

[0011] In this embodiment, the air outlet of the pressing blower is equipped with an air knife, and the outlet of the air knife is directly facing the upper surface of the conveyor belt.

[0012] In this embodiment, the pressure roller is a rubber-coated roller, and the pressing assembly is also provided with an elastic connection structure. The elastic connection structure connects the rubber-coated roller and the frame respectively, so that the rubber-coated roller forms a movement tendency to move closer to the upper surface of the conveyor belt.

[0013] In this embodiment, the elastic connection structure includes a first guide sleeve, a first guide post, a first spring, and a lifting block. The first guide post passes through the first guide sleeve and is connected to the lifting block. The first guide sleeve is located above the lifting block and connected to the frame. The first spring is sleeved outside the first guide post, and the two ends of the first spring abut against the first guide sleeve and the lifting block, respectively. The rubber-coated roller is rotatably connected to the lifting block.

[0014] In this embodiment, the low-stress FPC coating apparatus also includes a cutting assembly disposed on the frame, the cutting assembly being located on the side of the pressing fan away from the pressure roller.

[0015] In this embodiment, the conveyor belt is provided with several material support plates evenly distributed along the conveying direction, and a cutting gap is formed between each two adjacent material support plates. The cutting assembly includes a cutting drive mechanism and a cutting blade that matches the cutting gap. The cutting drive mechanism is connected to the frame, and the cutting blade is connected to the cutting drive mechanism.

[0016] In this embodiment, the cutting assembly further includes at least two sets of clamping structures. Clamping structures are provided on both sides of the cutting blade. Each clamping structure includes a second guide sleeve, a second guide post, a second spring, a lifting support rod, and a clamping wheel. The clamping wheel is rotatably connected to the lifting support rod and is located on the material support plate. The second guide post passes through the second guide sleeve and is connected to the lifting support rod. The second guide sleeve is located above the lifting support rod and connected to the frame. The second spring is sleeved outside the second guide post, and both ends of the second spring abut against the second guide sleeve and the lifting support rod, respectively.

[0017] The embodiments of this utility model have at least the following beneficial effects:

[0018] The protective film and FPC substrate are pressed and laminated using pressure rollers and a conveyor belt, achieving high pressing efficiency. An electrostatic neutralizer removes static electricity from the protective film before pressing, significantly reducing the electrostatic force between the protective film and the FPC substrate, effectively reducing lamination resistance and improving the lamination effect. The resulting lamination exhibits high flatness and tightness. Infrared heaters and pressing fans positioned along the conveying direction heat and soften the protective film, and gas extrusion achieves comprehensive and reliable compression lamination of the protective film and FPC substrate, effectively adapting to irregular contours of the FPC substrate. This effectively improves the consistency of the protective film's adhesion across the FPC body, resulting in a uniform and reliable lamination effect. Furthermore, the infrared heater is positioned between the pressure roller and the guide roller, with the protective film in this section mounted above the conveyor belt. This effectively ensures the distance between the infrared heater and the FPC body, reducing heat transfer and thus improving the FPC's reliability. Additionally, the pressing fan is positioned behind the pressure roller along the conveying direction, pre-pressing and positioning the protective film onto the FPC. This provides a stable foundation for the subsequent full lamination by the pressing fan, ensuring reliable lamination processing. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0020] Figure 1 This is a three-dimensional structural diagram of the low-stress FPC coating device according to an embodiment of the present invention;

[0021] Figure 2 This is a three-dimensional structural schematic diagram of the low-stress FPC coating device according to an embodiment of the present invention from another perspective.

[0022] Figure 3 for Figure 2 A magnified structural diagram of A in the middle;

[0023] Figure 4 This is a schematic front view of the low-stress FPC coating device according to an embodiment of the present invention.

[0024] Figure 5 This is a front view structural diagram of the low-stress FPC coating device according to an embodiment of the present invention during application.

[0025] Figure label:

[0026] Frame 100, conveyor belt 110, material support plate 111, cutting gap 112;

[0027] Film supply assembly 200, unwinding roller 210, guide roller 220, electrostatic neutralizer 230, ion fan 231, air filter 232;

[0028] Pressing assembly 300, pressure roller 310, infrared heater 320, pressing fan 330, air knife 331, elastic connection structure 340, first guide sleeve 341, first guide post 342, first spring 343, lifting block 344;

[0029] Cutting assembly 400, cutting drive mechanism 410, cutting blade 420, clamping structure 430, second guide sleeve 431, second guide post 432, second spring 433, lifting support rod 434, and clamping wheel 435. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0031] In the description of this utility model, it should be understood that the orientation descriptions, such as up, down, left, right, front, and back, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] In the description of this utility model, if the wire sleeve or bracket is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0033] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0034] FPC (Flexible Printed Circuit), also known as flexible circuit board, is a type of printed circuit board with high reliability and excellent flexibility, manufactured using polyimide or polyester film as the substrate. It is widely used in consumer electronics, automotive electronics, medical devices, and other fields. FPC lamination equipment is specialized equipment used to press a protective film or reinforcing plate onto the surface of an FPC substrate. It typically uses a roller pressing method to achieve the protective film application. During the pressing process, bubbles or wrinkles can easily form between the protective film and the surface of the FPC substrate due to impurities or stress, resulting in poor lamination quality. This is especially noticeable in irregularly shaped areas, where bubbles and wrinkles are more pronounced, leading to a decrease in FPC product quality and a low yield.

[0035] The following is for reference only. Figure 1 To be continued Figure 5 The present invention describes a low-stress FPC coating device that can reduce coating resistance, improve the overall coating adhesion, and achieve high coating reliability.

[0036] Reference Figures 1 to 5 A low-stress FPC coating device according to an embodiment of the present invention includes:

[0037] The frame 100 is equipped with a conveyor belt 110, which is used to drive the FPC body forward along the conveying direction;

[0038] The film supply assembly 200 is located above the conveyor belt 110 and connected to the frame 100. The film supply assembly 200 includes an unwinding roller 210, a guide roller 220 and an electrostatic neutralizer 230. The unwinding roller 210 and the guide roller 220 are both rotatably connected to the frame 100 and are both located above the conveyor belt 110. The electrostatic neutralizer 230 is fixedly connected to the frame 100 and is located above the conveyor belt 110. The unwinding roller 210 is used to unwind and supply the protective film, and the electrostatic neutralizer 230 is located on one side of the guide roller 220.

[0039] The pressing assembly 300 is located above the conveyor belt 110 and connected to the frame 100. The pressing assembly 300 includes a pressure roller 310, an infrared heater 320, and a pressing fan 330. The pressure roller 310 is rotatably connected to the frame 100 and located on the conveyor belt 110. The infrared heater 320 and the pressing fan 330 are fixedly connected to the frame 100 and are both located above the conveyor belt 110. The guide roller 220, infrared heater 320, pressure roller 310, and pressing fan 330 are arranged sequentially along the conveying direction. The pressure roller 310 is used to press the protective film onto the surface of the FPC body in conjunction with the conveyor belt 110. The guide rollers 220 are all located above the horizontal position of the pressure roller 310, so that the protective film wrapped around the guide rollers 220 and pressure roller 310... Inclined to the horizontal plane, this section of the protective film slopes downwards along the conveying direction, creating a sufficient gap between the protective film and the FPC body. The infrared heater 320 is positioned above the pressure roller 310 at its horizontal position, effectively ensuring that the heat from the infrared heater 320 is directed towards the protective film and away from the FPC body. The working end of the electrostatic neutralizer 230 faces the area between the pressure roller 310 and the guide roller 220, enabling the electrostatic neutralizer 230 to remove static electricity from the protective film wrapped around the guide roller 220 and the pressure roller 310. The working end of the pressing blower 330 faces the upper surface of the conveyor belt 110, allowing the pressing blower 330 to expel the gas between the protective film and the FPC body using air pressure, thereby reducing the bubble rate. Preferably, the infrared heater 320 can be configured as an infrared lamp with a reflector.

[0040] The protective film and the FPC substrate are pressed and laminated using the pressure roller 310 and the conveyor belt 110, achieving high pressing efficiency and low labor costs. The electrostatic neutralizer 230 removes static electricity from the protective film before pressing, significantly reducing the electrostatic force between the protective film and the FPC substrate, effectively reducing lamination resistance and improving the lamination effect, resulting in high flatness and tightness. The infrared heater 320 and the pressing fan 330, positioned along the conveying direction, heat and soften the protective film, and the gas extrusion method achieves comprehensive and reliable extrusion lamination of the protective film and the FPC substrate, effectively adapting to the irregular contours of the FPC substrate, thereby effectively improving the protective film's adhesion. The consistency of the bonding effect across the FPC body ensures a uniform and reliable lamination effect. Furthermore, the infrared heater 320 is positioned between the pressure roller 310 and the guide roller 220, with the protective film on the conveyor belt 110. This effectively ensures the distance between the infrared heater 320 and the FPC body, reducing heat transfer and improving the reliability of the FPC body. It also prevents damage due to high temperatures. Additionally, the pressing fan 330 is positioned behind the pressure roller 310 along the conveying direction. The pressure roller 310 pre-presses and positions the protective film onto the FPC, providing a stable bonding foundation for the subsequent full lamination by the pressing fan 330, ensuring reliable lamination processing.

[0041] It is understood that the electrostatic neutralizer 230 includes an ion fan 231 and an air filter 232. The outlet of the ion fan 231 faces the area between the pressure roller 310 and the guide roller 220. The outlet of the ion fan 231 is used to neutralize the charge of the protective film wrapped between the pressure roller 310 and the guide roller 220, thereby reducing the impact of static electricity on the lamination process. The air filter 232 is located at the inlet of the ion fan 231. The air filter 232 can effectively isolate impurities entering the ion fan 231, thereby effectively ensuring the purity of the ion airflow output by the ion fan 231. This significantly reduces secondary contamination of the protective film caused by the ion fan 231 during static electricity removal, further improving the reliability of the lamination process and resulting in a better lamination effect. Preferably, the air filter 232 can be a HEPA filter, also known as a high-efficiency air filter 232.

[0042] It is understood that the central axis of the outlet of the ion fan 231 is parallel to the horizontal plane. The ion fan 231 is located below the side of the guide roller 220 away from the pressure roller 310. The outlet of the ion fan 231 is located below the horizontal position of the guide roller 220, and the protective film surrounding the guide roller 220 and the pressure roller 310 is inclined at an angle α to the horizontal plane, where α ∈ [15°, 30°]. When the dimensions of the guide roller 220 and the pressure roller 310 are similar or the same, the plane containing the central axis of the guide roller 220 and the central axis of the pressure roller 310 forms an angle α with the horizontal plane.

[0043] During operation, the ion blower 231 is wound around a protective film between itself and the guide roller 220 and the pressure roller 310. The ion airflow output by the ion blower 231 advances below the protective film, which can reduce secondary pollution to the lower surface of the protective film used for adhesion. In conjunction with the air filter 232, secondary pollution can be further reduced. Moreover, the ion blower 231 delivers ion airflow to this section of the protective film at a small acute angle to achieve static electricity removal, which can ensure the effect of static electricity removal while reducing secondary pollution.

[0044] It should be noted that when the unwinding roller 210 is used to unwind a protective film containing carbon nanotubes, the ion fan 231 is located below the guide roller 220 on the side near the pressure roller 310. The ion fan 231 outputs an ion airflow to the upper surface of the protective film. By utilizing the effect of carbon nanotubes, the neutralizing charge can be transferred to the lower surface of the protective film, which can perform a comprehensive antistatic operation on the protective film and avoid secondary pollution to the lower surface of the protective film used for adhesion. This can significantly improve the film lamination effect. This FPC lamination device can effectively adapt to protective films containing carbon nanotubes.

[0045] Specifically, the low-stress FPC coating device of this utility model embodiment also includes a protective housing, which is wrapped around the frame 100 and is used to isolate an independent internal space from the external environment. This can effectively reduce the impact of environmental factors on the coating and bonding process, thereby effectively improving the reliability of the coating process.

[0046] It is understandable that the air outlet of the pressing blower 330 is equipped with an air knife 331. The air knife 331 has a converging channel that continuously contracts from top to bottom. The outlet of the air knife 331 faces the upper surface of the conveyor belt 110, and the horizontal projection of the air knife 331 passes through the opposite sides of the conveyor belt 110. By using the air knife 331 in conjunction with the pressing blower 330, a high-pressure airflow can be formed, which can effectively improve the overall compression and bonding effect.

[0047] It is understood that the pressure roller 310 is a rubber-coated roller, and the pressing assembly 300 is also provided with an elastic connection structure 340. The elastic connection structure 340 connects the rubber-coated roller and the frame 100 respectively, so that the rubber-coated roller forms a movement tendency to move closer to the upper surface of the conveyor belt 110. The elastic connection structure 340 can effectively improve the reliability of the pre-pressing effect, and the rubber-coated roller with good anti-slip performance can adapt to the conveying speed of the conveyor belt 110, and can achieve stable conveying action of the protective film and the FPC body.

[0048] It is understood that the elastic connection structure 340 includes a first guide sleeve 341, a first guide post 342, a first spring 343, and a lifting block 344. The first guide post 342 passes through the first guide sleeve 341 and is connected to the lifting block 344. The first guide sleeve 341 is located above the lifting block 344 and is connected to the frame 100. The first spring 343 is sleeved outside the first guide post 342. The upper and lower ends of the first spring 343 abut against the first guide sleeve 341 and the lifting block 344 respectively, so that the lifting block 344 forms a tendency to move away from the first guide sleeve 341. The rubber-coated roller is rotatably connected to the lifting block 344.

[0049] Preferably, there are two sets of elastic connection structures 340, both sets of elastic connection structures 340 are connected to the frame 100, and the rubber-coated roller is rotatably connected between the two sets of elastic connection structures 340.

[0050] Understandably, the low-stress FPC laminating apparatus also includes a cutting assembly 400 located on the frame 100. The cutting assembly 400 is located on the side of the pressing fan 330 away from the pressure roller 310 and is used to cut the FPC product obtained after lamination.

[0051] It is understood that the conveyor belt 110 is provided with several material support plates 111 evenly distributed along the conveying direction. The FPC body is placed on the material support plate 111, and a cutting gap 112 is formed between each two adjacent material support plates 111. The extending direction of the cutting gap 112 is perpendicular to the conveying direction. The cutting assembly 400 includes a cutting drive mechanism 410 and a cutting blade 420 matching the cutting gap 112. The cutting drive mechanism 410 is connected to the frame 100, and the cutting blade 420 is connected to the cutting drive mechanism 410. The driving direction of the cutting drive mechanism 410 is perpendicular to the conveying direction. The cutting drive mechanism 410 is used to drive the cutting blade 420 to move along the cutting gap 112, thereby cutting and separating the FPC products obtained by the lamination process. Preferably, the material support plate 111 is a flexible plate structure, which can adapt to the movement of the conveyor belt 100 and effectively ensure the reliability of the conveying action. The cutting drive mechanism 410 can be a linear drive module, such as a synchronous belt translation drive mechanism or a lead screw translation mechanism.

[0052] It is understood that the cutting assembly 400 also includes at least two sets of clamping structures 430. Along the conveying direction, clamping structures 430 are provided on opposite sides of the cutting blade 420 to provide a stable positioning base for the cutting action. Each clamping structure 430 includes a second guide sleeve 431, a second guide post 432, a second spring 433, a lifting support rod 434, and a clamping wheel 435. The clamping wheel 435 is rotatably connected to the lifting support rod 434. The central axis of the clamping wheel 435 is parallel to the central axis of the pressure roller 310. The clamping wheel 435 is located on the material support plate 111. The second guide post... The second guide post 432 is inserted into the second guide sleeve 431. The second guide post 432 is connected to the lifting support rod 434. The second guide sleeve 431 is located above the lifting support rod 434 and connected to the frame 100. The second spring 433 is sleeved on the outside of the second guide post 432. The upper and lower ends of the second spring 433 abut against the second guide sleeve 431 and the lifting support rod 434 respectively, so that the pressure roller 435 forms a tendency to move closer to the conveyor belt 110, thereby pressing the FPC product obtained by film coating onto the material support plate 111, which can effectively improve the stability of the cutting action.

[0053] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A low-stress FPC coating device, characterized in that, include: The frame (100) is equipped with a conveyor belt (110) for driving the FPC body forward along the conveying direction; A film supply assembly (200) is located above the conveyor belt (110) and connected to the frame (100). The film supply assembly (200) includes an unwinding roller (210), a guide roller (220), and an electrostatic neutralizer (230). The unwinding roller (210) is used to unwind the protective film, and the electrostatic neutralizer (230) is located on one side of the guide roller (220). A pressing assembly (300) is located above the conveyor belt (110) and connected to the frame (100). The pressing assembly (300) includes a pressure roller (310), an infrared heater (320), and a pressing fan (330). The guide roller (220), the infrared heater (320), the pressure roller (310), and the pressing fan (330) are arranged sequentially along the conveying direction. The pressure roller (310) is used to cooperate with the conveyor belt (110). The protective film is pressed onto the surface of the FPC body. The guide rollers (220) are all located above the horizontal position of the pressure roller (310) so that the protective film wrapped around the guide roller (220) and the pressure roller (310) is inclined to the horizontal plane. The working end of the electrostatic neutralizer (230) is directly opposite the area between the pressure roller (310) and the guide roller (220). The working end of the pressing fan (330) is directly opposite the conveyor belt (110).

2. The low-stress FPC coating device according to claim 1, characterized in that, The electrostatic neutralizer (230) includes an ion fan (231) and an air filter (232). The outlet of the ion fan (231) is directly opposite the area between the pressure roller (310) and the guide roller (220), and the air filter (232) is located at the inlet of the ion fan (231).

3. The low-stress FPC coating device according to claim 2, characterized in that, The central axis of the air outlet of the ion fan (231) is parallel to the horizontal plane, and the ion fan (231) is located below the guide roller (220) on the side away from the pressure roller (310).

4. The low-stress FPC coating device according to claim 1, characterized in that, The air outlet of the pressing blower (330) is provided with an air knife (331), and the outlet of the air knife (331) is directly facing the upper surface of the conveyor belt (110).

5. The low-stress FPC coating device according to claim 1, characterized in that, The pressure roller (310) is a rubber-coated roller, and the pressing assembly (300) is also provided with an elastic connection structure (340). The elastic connection structure (340) connects the rubber-coated roller and the frame (100) respectively, so that the rubber-coated roller forms a movement tendency to move closer to the upper surface of the conveyor belt (110).

6. The low-stress FPC coating apparatus according to claim 5, characterized in that, The elastic connection structure (340) includes a first guide sleeve (341), a first guide post (342), a first spring (343), and a lifting block (344). The first guide post (342) passes through the first guide sleeve (341) and is connected to the lifting block (344). The first guide sleeve (341) is located above the lifting block (344) and connected to the frame (100). The first spring (343) is sleeved outside the first guide post (342). The two ends of the first spring (343) abut against the first guide sleeve (341) and the lifting block (344) respectively. The rubber-coated roller is rotatably connected to the lifting block (344).

7. The low-stress FPC coating apparatus according to claim 1, characterized in that, It also includes a cutting assembly (400) disposed on the frame (100), the cutting assembly (400) being located on the side of the pressing blower (330) away from the pressure roller (310).

8. A low-stress FPC coating apparatus according to claim 7, characterized in that, The conveyor belt (110) is provided with a plurality of material support plates (111) evenly distributed along the conveying direction. A cutting gap (112) is formed between each two adjacent material support plates (111). The cutting assembly (400) includes a cutting drive mechanism (410) and a cutting blade (420) matching the cutting gap (112). The cutting drive mechanism (410) is connected to the frame (100), and the cutting blade (420) is connected to the cutting drive mechanism (410).

9. A low-stress FPC coating apparatus according to claim 8, characterized in that, The cutting assembly (400) further includes at least two sets of clamping structures (430). Each cutting blade (420) has a clamping structure (430) on both opposite sides. Each clamping structure (430) includes a second guide sleeve (431), a second guide post (432), a second spring (433), a lifting support rod (434), and a clamping wheel (435). The clamping wheel (435) is rotatably connected to the lifting support rod (434). The clamping wheel (435) is located on the material support plate (111). On the frame (100), the second guide post (432) passes through the second guide sleeve (431), the second guide post (432) is connected to the lifting support rod (434), the second guide sleeve (431) is located above the lifting support rod (434) and connected to the frame (100), the second spring (433) is sleeved outside the second guide post (432), and the two ends of the second spring (433) abut against the second guide sleeve (431) and the lifting support rod (434) respectively.

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