Directional guiding high-precision stretching equipment for uniaxial stretching polyethylene film

Abstract

The invention discloses high-precision stretching equipment for directionally guiding a uniaxial stretching polyethylene film, comprising: a main body unit, which comprises a machine base and a conveying platform fixedly mounted on the machine base; the rolling unit is arranged on the machine base and comprises a pressing roller movably installed on the machine base and a heating assembly arranged in the pressing roller, and the heating assembly cooperates with the pressing roller to press the polyethylene film into the uniform thickness; and the preheating unit is arranged above the feeding end of the conveying platform and comprises a monitoring assembly, an air outlet bin and a plurality of heat mixing assemblies, the thickness change of the polyethylene film is monitored through the monitoring assembly, and then the heat mixing assemblies at the corresponding positions regulate and control the air outlet temperature to reinforce hot melting of the polyethylene film exceeding the standard thickness range. Through cooperation of the preheating unit and the rolling unit, accurate dynamic preheating and efficient rolling correction of the polyethylene film are achieved, the thickness of the polyethylene film is efficiently unified, wrinkles are eliminated, and the stretching processing efficiency and the finished product quality of the polyethylene film are effectively improved.

Description

Technical Field

[0001] This invention relates to the technical field of polyethylene film production and processing, and in particular to a high-precision stretching device for unidirectional stretching and guiding of polyethylene film. Background Technology

[0002] Polyethylene film is a thin film made primarily from polyethylene resin through extrusion, casting, or blow molding. Due to its good flexibility, chemical resistance, and low cost, it is widely used in packaging, agriculture, and industrial protection. Uniaxially oriented polyethylene film, produced by stretching in a single direction, aligns the molecular chains, significantly improving its tensile strength and tear resistance.

[0003] Currently, most mainstream polyethylene film stretching equipment uses roller stretching technology, but this method has significant drawbacks in practical applications. On one hand, insufficient matching precision of the stretching roller speeds and uneven stress distribution across different areas of the film during the stretching stage can easily lead to large transverse and longitudinal thickness deviations, affecting product consistency. On the other hand, to eliminate wrinkles generated during stretching and improve thickness uniformity, the equipment is usually equipped with pressure roller assemblies. However, the pressure rollers rely on a preheating system to regulate the film temperature. Existing preheating devices mostly use overall heating, lacking precise control over local film temperature. When initial thickness differences exist in the film, uneven preheating further exacerbates thickness deviations during stretching. Furthermore, excessive preheating can cause the film to melt and deform, reducing product yield. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the prior art, the present invention is proposed. The technical problem to be solved by the present invention is that it is difficult to accurately control the local temperature of the film when the existing stretching equipment preheats the polyethylene film.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-precision stretching device for unidirectional stretching of polyethylene film, comprising: a main unit, which includes a base and a conveying platform fixedly installed on the base; The roll forming unit is mounted on a machine base and includes a pressure roller movably mounted on the machine base and a heating component disposed inside the pressure roller. The heating component works with the pressure roller to press the polyethylene film to a uniform thickness. The preheating unit is located above the feed end of the conveying platform. It includes a monitoring component, an air outlet chamber located on one side of the monitoring component, and multiple heat mixing components located on the air outlet chamber. The monitoring component monitors the change in the thickness of the polyethylene film, and for polyethylene films that exceed the standard thickness range, the corresponding heat mixing components adjust the air outlet temperature to enhance the heat melting.

[0007] As a preferred embodiment of the high-precision stretching device for unidirectional stretching of polyethylene film according to the present invention, the heat mixing assembly includes a mixing chamber fixedly installed above the air outlet chamber, and the mixing chamber is connected to the air outlet chamber. Two air inlet pipes are fixedly connected above the mixing chamber, one of which is fixedly connected to a hot air pipe at its air inlet end, and the other is fixedly connected to a cold air pipe at its air inlet end.

[0008] As a preferred embodiment of the high-precision stretching equipment for directional guidance of unidirectional stretching polyethylene film according to the present invention, the heat mixing assembly further includes a fixed shaft fixedly installed in the mixing chamber, a guide member rotatably sleeved on the fixed shaft, a sliding groove opened at both ends of the guide member, a sliding rod slidably inserted in the sliding groove, a support member fixedly installed on the sliding rod, and an air control plug fixedly connected to the end of the support member, the air control plug being slidably inserted in the air inlet pipe. Two sets of limiting grooves are symmetrically opened on the inner wall of the mixing chamber. The ends of two sliding rods are slidably inserted into the two sets of limiting grooves respectively. A first electric push rod is fixedly installed on the mixing chamber. The telescopic end of the first electric push rod passes through the wall of the mixing chamber and is fixedly connected to one of the sliding rods.

[0009] As a preferred embodiment of the high-precision stretching equipment for unidirectional stretching of polyethylene film according to the present invention, wherein: an air guide plate is fixedly installed inside the air outlet chamber, and a first connecting frame is fixedly connected to both sides of the air outlet chamber, and the first connecting frame is fixedly connected to the side of the base. Two air supply pipes are symmetrically fixedly connected to the first connecting frame, one of which is fixedly connected to multiple hot air pipes and the other is fixedly connected to multiple cold air pipes.

[0010] As a preferred embodiment of the high-precision stretching device for unidirectional stretching of polyethylene film according to the present invention, the pressure roller includes a cylinder and a disc disposed at both ends of the cylinder. An annular groove is provided on the side of the disc near the cylinder, and a ring is rotatably installed on the annular groove. The ring is fixedly connected to the end of the cylinder.

[0011] As a preferred embodiment of the high-precision stretching equipment for unidirectional stretching of polyethylene film according to the present invention, wherein: fixed seats are fixedly connected to both sides of the base, a second electric push rod is fixedly installed on the fixed seat, a support seat is fixedly installed on the telescopic end of the second electric push rod, a support frame is fixedly connected to the support seat, and multiple air guide pipes are fixedly connected to the support frame, and the air guide pipes penetrate the disc.

[0012] As a preferred embodiment of the high-precision stretching device for unidirectional stretching of polyethylene film according to the present invention, the heating component includes a heating rod disposed inside the cylinder, a third electric push rod fixedly installed on the support base, a guide frame fixedly connected to the telescopic end of the third electric push rod, a connector slidably inserted in the guide frame, and the connector being fixedly connected to the heating rod, and an oblique groove opened on the disc, the connector being slidably inserted in the oblique groove.

[0013] As a preferred embodiment of the high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to the present invention, the machine base is provided with a cooling roller for rapid cooling of polyethylene film. The cooling roller is located on the side of the rolling unit away from the preheating unit. Supports are fixedly connected to both sides of the cooling roller, and the supports are fixedly connected to the support base.

[0014] As a preferred embodiment of the high-precision stretching equipment for unidirectional stretching of polyethylene film according to the present invention, a plurality of guide grooves are provided on both sides of the machine base and below the roller pressing unit, and a limiting rod is slidably inserted in the guide groove, and the limiting rod is fixedly connected to the support base.

[0015] As a preferred embodiment of the high-precision stretching device for unidirectional stretching of polyethylene film according to the present invention, the monitoring component includes a positioning frame fixedly installed above the conveying platform. Multiple sensors for measuring the thickness of polyethylene film are equidistantly arranged on the bottom surface of the positioning frame near the conveying platform, and the sensors are electrically connected to the first electric push rod and the third electric push rod.

[0016] The beneficial effects of this invention are: 1. By setting up a preheating unit, the preheating effect is optimized, the difficulty of subsequent processing is reduced, and the outlet air temperature of the corresponding area mixing component can be independently adjusted according to the local thickness change of the membrane, so as to accurately match the local process requirements and avoid processing defects caused by improper overall preheating temperature.

[0017] 2. By setting up a heat mixing component, the thickness of the polyethylene film can be detected in real time by the sensor of the monitoring component. When the film thickness exceeds the standard threshold, the ratio of cold and hot air intake can be adjusted by driving the air control plug of the heat mixing component through the first electric push rod. There is no need to wait for the heat source to store / release heat, and the temperature of the mixed airflow can be changed instantly. Moreover, the temperature control accuracy is much higher than that of the traditional single heat source temperature control mode.

[0018] 3. By setting up a roller pressing unit, it can ensure that the pressure is evenly transmitted during extrusion molding, eliminate film wrinkles and correct thickness fluctuations, and avoid excessive softening, adhesion or deformation of the film. When encountering ultra-thick film, the heating rod can be angled closer to the cylinder area in contact with the ultra-thick film to prolong the contact time between the heat source and the film, ensure that the heat penetrates fully, soften the ultra-thick film, facilitate precise extrusion correction by the cylinder, and avoid incomplete correction or thickness rebound. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the overall structure of the high-precision stretching device for unidirectional stretching and guiding of polyethylene film according to the present invention. Figure 2 A three-dimensional structural schematic diagram of the preheating unit provided by the present invention; Figure 3 A cross-sectional structural diagram of the preheating unit provided by the present invention; Figure 4 A three-dimensional structural schematic diagram of the heat mixing component provided by the present invention; Figure 5 A partial three-dimensional structural schematic diagram of the preheating unit provided by the present invention; Figure 6 This is a schematic diagram of the internal structure of the cylinder provided by the present invention.

[0020] Explanation of reference numerals in the attached figures: 100. Main unit; 101. Machine base; 102. Conveying platform; 103. Unwinding roll; 104. Rewinding roll; 200. Roller pressing unit; 201. Press roller; 201a. Cylinder; 201b. Disc; 201c. Annular groove; 201d. Ring; 201e. Inclined groove; 202. Heating assembly; 202a. Heating rod; 202b. Third electric push rod; 202c. Guide frame; 202d. Connector; 203. Fixed base; 204. Second electric push rod; 205. Support base; 206. Support frame; 207. Air duct; 208. Guide groove; 209. Limiting rod; 300, Preheating unit; 301, Monitoring component; 301a, Positioning frame; 302, Air outlet chamber; 303, Heat mixing component; 303a, Mixing chamber; 303b, Air inlet duct; 303c, Hot air duct; 303d, Cold air duct; 303e, Fixed shaft; 303f, Guide component; 303g, Slide groove; 303h, Sliding rod; 303i, Support component; 303j, Air control plug; 303k, Limiting groove; 303m, First electric push rod; 303n, Air supply duct; 304, Air guide plate; 305, First connecting frame; 400, Cooling roller; 401, Support. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Example Reference Figure 1 - Figure 6 This embodiment provides a high-precision stretching device for unidirectional stretching of polyethylene film, including a main unit 100. The main unit 100 includes a base 101 and a conveying platform 102 fixedly installed on the base 101. An unwinding roller 103 and a rewinding roller 104 are fixedly installed on the base 101 and respectively on both sides of the conveying platform 102. The polyethylene film is output by the unwinding roller 103, and after passing through the conveying platform 102, it is recovered by the rewinding roller 104. The base 101 is equipped with a preheating unit 300 and a rolling unit 200. The preheating unit 300 is located above the feed end of the conveying platform 102 and includes a monitoring component 301, an air outlet chamber 302 located on one side of the monitoring component, and multiple heat mixing components 303 located on the air outlet chamber 302. The monitoring component 301 monitors the change in polyethylene film thickness, and for polyethylene films that exceed the standard thickness range, the corresponding heat mixing components 303 adjust the air outlet temperature to enhance heat melting. The rolling unit 200 includes a pressure roller 201 movably mounted on the base 101 and a heating component 202 located inside the pressure roller 201. The heating component 202 works with the pressure roller 201 to press the polyethylene film to a uniform thickness. Through the cooperation of the preheating unit 300 and the rolling unit 200, precise preheating and efficient wrinkle removal of the polyethylene film are achieved, and the thickness of the polyethylene film is efficiently uniform.

[0023] like Figure 2 - Figure 4 As shown, the heat mixing assembly 303 includes a mixing chamber 303a fixedly installed above the air outlet chamber 302, and the mixing chamber 303a is connected to the air outlet chamber 302. Two air inlet pipes 303b are fixedly connected above the mixing chamber 303a. One air inlet pipe 303b is fixedly connected to a hot air pipe 303c at its air inlet end, and the other air inlet pipe 303b is fixedly connected to a cold air pipe 303d at its air inlet end, so as to introduce hot air and cold air in different proportions into the mixing chamber 303a, thereby achieving precise and rapid adjustment of the air outlet temperature to meet the dynamic requirements of different polyethylene film thicknesses for airflow temperature.

[0024] This design actively regulates the mixing ratio of hot and cold air, utilizing the instantaneous heat exchange characteristics of gas mixing to replace the passive temperature control mode of traditional single heat source start / stop / power adjustment. There is no need to wait for the heat source (such as heating element) to store and release heat; simply adjusting the opening of the air valve can instantly change the ratio of hot and cold air, and the mixing temperature changes accordingly. Furthermore, by precisely controlling the air volume ratio of hot and cold air, its effect is far superior to the temperature control accuracy of traditional single heat source.

[0025] The heat mixing assembly 303 also includes a fixed shaft 303e fixedly installed in the mixing chamber 303a. The fixed shaft 303e serves as the rotational support reference for the guide member 303f, providing a stable rotation axis for the guide member 303f and ensuring that the guide member 303f always rotates around the fixed shaft 303e during movement, avoiding adjustment deviation of the control plug 303j due to offset. The guide member 303f is rotatably sleeved on the fixed shaft 303e. The function of the guide member 303f is to simultaneously control the alternating raising and lowering of the two sliding rods 303h and ensure the synchronization of the adjustment actions of the two control plugs 303j. Both ends of the guide member 303f are provided with sliding grooves 303g. Because the movement trajectory of the guide member 303f at both ends is arc-shaped when it rotates around the fixed shaft 303e, without the sliding grooves 303g, the guide member 303f would be directly... If 03f is rigidly connected to the sliding rod 303h, the sliding rod 303h will also be forced to move along an arc. This cannot meet the requirement of the air control plug 303j moving vertically back and forth in the air inlet pipe 303b. However, by setting the sliding groove 303g, the end of the guide member 303f can drive the sliding rod 303h to move linearly while moving in an arc. The sliding rod 303h is slidably inserted in the sliding groove 303g. Two sets of limiting grooves 303k are symmetrically opened on the inner wall of the mixing chamber 303a. The ends of the two sliding rods 303h are respectively slidably inserted in the two sets of limiting grooves 303k. The limiting grooves 303k restrict the movement trajectory of the sliding rod 303h, so that it can only move vertically back and forth, avoiding the sliding rod 303h from deviating or shaking during the movement, and ensuring that the air control plug 303j is accurately inserted into the air inlet pipe 303b.

[0026] A support member 303i is fixedly installed on the sliding rod 303h. A control plug 303j is fixedly connected to the end of the support member 303i. The control plug 303j is slidably inserted into the air inlet pipe 303b. The control plug 303j is usually a conical or cylindrical structure and is adapted to the inner wall of the air inlet pipe 303b. The control plug 303j directly adjusts the ventilation cross-sectional area of ​​the air inlet pipe 303b, thereby controlling the air volume of hot or cold air. When the control plug 303j goes deeper into the air inlet pipe 303b, the ventilation cross-sectional area decreases and the air volume decreases; when the control plug 303j goes outward, the ventilation cross-sectional area increases and the air volume increases. Through the coordinated adjustment of the control plugs 303j in the two air inlet pipes 303b, the mixing ratio of hot and cold air can be precisely controlled, and the outlet air temperature can be regulated.

[0027] It should be added that the maximum diameter of the air control plug 303j will not be equal to or nearly equal to the diameter of the air inlet pipe 303b. The air control plug 303j will not completely block the air inlet pipe 303b, resulting in the air outlet chamber 302 only discharging hot air or only discharging cold air. Because the preheating unit 300 always preheats the polyethylene film, when the thickness of the polyethylene film is within the standard threshold, the preheating unit 300 will also supply the polyethylene film with a temperature lower than that of the rolling unit 200. This is to pre-soften the polyethylene film before it enters the rolling process, reduce the difficulty of rolling, eliminate internal stress, avoid deformation after rolling, and achieve uniform heating, providing stable process conditions for subsequent rolling molding or composite processing. In the initial state, the mixing assembly 303 has one air control plug 303j completely slidably inserted into the air inlet pipe 303b of the docking hot air pipe 303c, and the other air control plug 303j completely away from the air inlet pipe 303b of the docking cold air pipe 303d. At this time, it is the minimum temperature for preheating the polyethylene film.

[0028] A first electric push rod 303m is fixedly installed on the mixing chamber 303a. The telescopic end of the first electric push rod 303m penetrates the wall of the mixing chamber 303a and is fixedly connected to one of the sliding rods 303h. The first electric push rod 303m is the power source for controlling the ratio of hot and cold air. The first electric push rod 303m receives electrical signals to realize its telescopic movement, directly driving the sliding rod 303h to move, thereby driving a series of subsequent components to move in tandem. When the polyethylene film thickness is detected to exceed the standard threshold, the first electric push rod 303m controls the corresponding sliding rod 303h to rise and fall, thereby adjusting the sliding depth of the two air control plugs 303j in the air inlet plug, thereby achieving rapid adjustment of the airflow temperature. The greater the amount by which the polyethylene film thickness exceeds the threshold, the further the air control plug 303j is from the air inlet pipe 303b connected to the hot air pipe 303c, and the higher the temperature of the outlet air, thus making the corresponding polyethylene film melt more thoroughly. Multiple heat mixing components 303 are installed on the air outlet chamber 302. If the polyethylene film has local thickness changes, the air outlet temperature of the corresponding heat mixing component 303 can be independently adjusted to accurately match the process requirements of the local thickness of the polyethylene film, thereby optimizing the subsequent processing quality.

[0029] An air guide plate 304 is fixedly installed inside the air outlet chamber 302. The air guide plate 304 guides, diverts, and homogenizes the airflow output by the heat mixing component 303, ensuring that the airflow acts on the corresponding polyethylene film surface with a stable and uniform wind speed and temperature. A first connecting frame 305 is fixedly connected to both sides of the air outlet chamber 302, and the first connecting frame 305 is fixedly connected to the side of the base 101. The first connecting frame 305 supports the air outlet chamber 302 and the heat mixing component 303. Two air supply pipes 303n are symmetrically fixedly connected to the first connecting frame 305. One of them is fixedly connected to multiple hot air pipes 303c, and the other is fixedly connected to multiple cold air pipes 303d. The airflow temperature supplied by the two air supply pipes 303n is a stable temperature.

[0030] like Figure 1 , Figure 5 and Figure 6 As shown, the pressure roller 201 includes a cylinder 201a and discs 201b disposed at both ends of the cylinder 201a. An annular groove 201c is formed on the side of the disc 201b near the cylinder 201a. A ring 201d is rotatably mounted on the annular groove 201c and is fixedly connected to the end of the cylinder 201a. Fixed seats 203 are fixedly connected to both sides of the machine base 101. A second electric push rod 204 is fixedly mounted on the fixed seat 203. A support seat 205 is fixedly mounted on the telescopic end of the second electric push rod 204. A support frame 206 is fixedly connected to the support seat 205. Multiple air guide pipes 207 are fixedly connected to the support frame 206. Specifically, the fixed base 203 fixes the second electric push rod 204 to both sides of the machine base 101 through the disc 201b. The second electric push rod 204 adjusts the distance between the roller pressing assembly and the polyethylene film by adjusting the height of the support base 205, thereby facilitating the flexible setting of the standard thickness threshold of the film. The lowest point of the cylinder 201a is the thickest value of the standard thickness threshold of the polyethylene film. The disc 201b is fixed on the support frame 206 through the air guide pipe 207. The cylinder 201a adheres to the polyethylene film and rotates relative to the disc 201b in the annular groove 201c through the ring 201d as the film moves. The cylinder 201a presses the polyethylene film into a uniform standard thickness.

[0031] Furthermore, multiple guide grooves 208 are provided on both sides of the machine base 101 and below the roller pressing unit 200. A limiting rod 209 is slidably inserted in the guide groove 208 and is fixedly connected to the support base 205. Through the setting of the guide groove 208 and the limiting rod 209, the connection between the support base 205 and the machine base 101 can be strengthened, thereby making the support base 205 more stable during the lifting process.

[0032] It should be added that the multiple air ducts 207 have the functions of injecting cold air into the cylinder 201a and discharging mixed hot air to ensure uniform heating and stable air pressure inside the cylinder 201a. When it is detected that some polyethylene film exceeds the standard threshold, the heating rod 202a will increase the heat energy and move closer to the part of the cylinder 201a that will contact the polyethylene film that needs to be reinforced by rolling, until it is reset after the operation is completed. During this process, the temperature inside the cylinder 201a will rise. In order to avoid the excessively hot cylinder 201a pressing the polyethylene film within the standard threshold, the air ducts 207 will quickly inject air into the cylinder 201a for cooling inside the cylinder 201a in a short time to avoid the polyethylene film with qualified thickness from being overheated and melted.

[0033] The heating assembly 202 includes a heating rod 202a disposed inside the cylinder 201a. In its initial state, the heating rod 202a maintains the cylinder 201a at a constant temperature, preventing the polyethylene film from becoming excessively softened, losing its shape, or sticking together. During the process of the cylinder 201a extruding and shaping the polyethylene film to eliminate wrinkles and correct thickness fluctuations, this constant temperature state ensures uniform pressure transmission, further improving the thickness accuracy and surface smoothness of the polyethylene film. Furthermore, in the event of an excessively thick polyethylene film, the initial constant temperature state of the cylinder 201a can... This design eliminates the need for the heating rod 202a to reheat from room temperature. Instead, a slight increase in power is sufficient to raise the temperature, significantly reducing the response time from detecting film thickness exceeding the threshold to initiating temperature control. This avoids the problem of slow start-up of the heating rod 202a, facilitating rapid adjustment of the excessively thick polyethylene film in conjunction with the cylinder 201a. It also helps prevent damage to the polyethylene film and cylinder 201a due to sudden temperature changes. Initial constant temperature ensures that the film and pressure roller 201 remain in a stable temperature environment, guaranteeing processing quality and equipment lifespan.

[0034] A third electric push rod 202b is fixedly installed on the support base 205. A guide frame 202c is fixedly connected to the telescopic end of the third electric push rod 202b. A connector 202d is slidably inserted into the guide frame 202c and is fixedly connected to the heating rod 202a. An inclined groove 201e is opened on the disc 201b. The connector 202d is slidably inserted into the inclined groove 201e. Specifically, the third electric push rod 202b controls the sliding of the connector 202d through the guide frame 202c, thereby causing the connector 202d to drive the heating rod 202a to slide along the guide direction of the inclined groove 201e.

[0035] The purpose of this design is to allow the heat source to quickly approach the polyethylene film to be processed. Since heat conduction also takes a certain amount of time, and the polyethylene film passes through the cylinder 201a for a very short time, the heating rod 202a will increase its temperature and slide along the inclined groove 201e to approach the part of the cylinder 201a that is attached to the polyethylene film. This allows the heat to be quickly transferred to the area of ​​the film that needs to be corrected in the short time that the polyethylene film passes through the cylinder 201a, thus achieving rapid correction of the polyethylene film.

[0036] Meanwhile, compared to the design that allows the heating rod 202a to descend vertically to contact the cylinder 201a, since the lowest point of the cylinder 201a corresponds to the maximum thickness of the standard film, the polyethylene film within the standard thickness threshold will only quickly and briefly contact the lowest point of the cylinder 201a. However, when the film thickness exceeds the standard threshold, the thicker part will contact the surface of the cylinder 201a before reaching the lowest point. Based on this characteristic, the oblique trajectory design of the oblique groove 201e has a unique advantage: it does not allow the heating rod 202a to approach the cylinder 201a only in the vertical direction, but through oblique guidance, the heating rod 202a drives the heat source to gradually approach and act on the cylinder 201a along the tangential direction of the surface of the cylinder 201a or a preset oblique path.

[0037] This design ensures that after the membrane to be corrected makes early contact with the cylinder 201a, the contact process between the membrane and the heating source (i.e., heating rod 202a) of the cylinder 201a is no longer a brief point contact or instantaneous contact, but rather forms a longer line contact or surface contact journey. Specifically, when the ultra-thick membrane makes early contact with the cylinder 201a, the oblique trajectory design of the oblique groove 201e allows the cylinder 201a to continue heating along the oblique direction after contact with the membrane, rather than the heating source quickly reaching the lowest point of the cylinder 201a and then disengaging from contact, thereby effectively extending the contact time between the heating source and the membrane.

[0038] This extended contact time provides a more sufficient heat conduction window for the heating rod 202a, ensuring that the heat can fully penetrate into the ultra-thick area of ​​the film and achieve the ideal softening degree, creating favorable conditions for the subsequent precise shaping by the pressure roller 201. On the other hand, the longer contact time allows the pressure roller 201 to exert a more thorough squeezing and correction effect on the film, avoiding incomplete correction due to insufficient contact time, and preventing problems such as thickness rebound or local unevenness. Ultimately, this significantly improves the accuracy and stability of ultra-thick film thickness correction, ensuring that the quality of the finished film meets the standard requirements.

[0039] like Figure 1 As shown, a cooling roller 400 for rapidly cooling polyethylene film is provided on the base 101. The cooling roller 400 is located on the side of the pressing unit 200 away from the preheating unit 300. By setting the cooling roller 400, the hot-pressed polyethylene film can be rapidly cooled and shaped, avoiding rebound, shrinkage or deformation such as thickness rebound and surface wrinkling, which would cause the effect of the previous hot pressing correction to fail and fail to meet the standard requirements. In addition, cooling the polyethylene film can also avoid the problem of interlayer adhesion caused by the softening of the film during winding, which would lead to difficulties in unwinding or even damage to the film. Supports 401 are fixedly connected to both sides of the cooling roller 400, and the supports 401 are fixedly connected to the support base 205. The supports 401 support the cooling roller 400 and allow the cooling roller 400 to be adjusted in height together with the pressing roller 201.

[0040] It should be added that the monitoring component 301 includes a positioning frame 301a fixedly installed above the conveying platform 102. Multiple sensors for measuring the thickness of polyethylene film are equidistantly arranged on the bottom surface of the positioning frame 301a near the conveying platform 102. The sensors are electrically connected to the first electric push rod 303m and the third electric push rod 202b. When the polyethylene film passes through the conveying platform 102, the sensors continuously monitor the film thickness value and compare it with the preset standard thickness threshold in real time.

[0041] When the sensor detects that the overall thickness of a certain area of ​​the membrane is too high, the control system simultaneously sends electrical signals to the first electric push rod 303m and the third electric push rod 202b: if the membrane is too thick, the first electric push rod 303m controls the mixing component 303 corresponding to the preheating unit 300 to increase the proportion of hot air, raise the preheating temperature, and enhance the softening of the membrane. The electric push rod retracts its telescopic end, causing the heating rod 202a, whose temperature has increased, to slide along the inclined groove 201e. After the membrane that needs correction passes through the preheating unit 300, the heating rod 202a moves to... At the lowest end of the inclined groove 201e, the heat conduction efficiency of the local area is rapidly enhanced by the dual effects of proximity to the heat source and temperature increase, so that the ultra-thick film is fully softened in a short time, which facilitates the precise extrusion and correction of the excessively thick polyethylene film by the pressure roller 201. The control system will determine the reset time of the first electric push rod 303m and the third electric push rod 202b based on the moving speed of the film. It should be added that if the film is too thin, the preheating unit 300 will preheat the part of the film and other thicker parts normally, and it can still be corrected when passing through the roller pressing unit 200.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-precision stretching device for unidirectional stretching and guiding of polyethylene film, characterized in that: include: The main unit (100) includes a base (101) and a conveying platform (102) fixedly mounted on the base (101). A roller pressing unit (200) is provided on a machine base (101), which includes a pressure roller (201) movably mounted on the machine base (101) and a heating component (202) provided inside the pressure roller (201). The heating component (202) works with the pressure roller (201) to press the polyethylene film to a uniform thickness. The preheating unit (300) is located above the feed end of the conveying platform (102). It includes a monitoring component (301), an air outlet chamber (302) located on one side of the monitoring component, and multiple heat mixing components (303) located on the air outlet chamber (302). The monitoring component (301) monitors the change in the thickness of the polyethylene film, and then for polyethylene films that exceed the standard thickness range, the corresponding heat mixing components (303) adjust the air outlet temperature to enhance the heat melting.

2. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 1, characterized in that: The heat mixing assembly (303) includes a mixing chamber (303a) fixedly installed above the air outlet chamber (302), and the mixing chamber (303a) is connected to the air outlet chamber (302). Two air inlet pipes (303b) are fixedly connected above the mixing chamber (303a). One air inlet pipe (303b) is fixedly connected to a hot air pipe (303c) at its air inlet end, and the other air inlet pipe (303b) is fixedly connected to a cold air pipe (303d) at its air inlet end.

3. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 2, characterized in that: The heat mixing assembly (303) also includes a fixed shaft (303e) fixedly installed in the mixing chamber (303a). A guide (303f) is rotatably sleeved on the fixed shaft (303e). Slide grooves (303g) are opened at both ends of the guide (303f). A sliding rod (303h) is slidably inserted in the slide groove (303g). A support (303i) is fixedly installed on the sliding rod (303h). A wind control plug (303j) is fixedly connected to the end of the support (303i). The wind control plug (303j) is slidably inserted in the air inlet pipe (303b). Two sets of limiting grooves (303k) are symmetrically opened on the inner wall of the mixing chamber (303a). The ends of two sliding rods (303h) are slidably inserted into the two sets of limiting grooves (303k). A first electric push rod (303m) is fixedly installed on the mixing chamber (303a). The telescopic end of the first electric push rod (303m) passes through the wall of the mixing chamber (303a) and is fixedly connected to one of the sliding rods (303h).

4. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 1, characterized in that: An air guide plate (304) is fixedly installed inside the air outlet chamber (302). A first connecting frame (305) is fixedly connected to both sides of the air outlet chamber (302), and the first connecting frame (305) is fixedly connected to the side of the base (101). Two air supply pipes (303n) are symmetrically fixedly connected to the first connecting frame (305), one of which is fixedly connected to multiple hot air pipes (303c), and the other is fixedly connected to multiple cold air pipes (303d).

5. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 1, characterized in that: The pressure roller (201) includes a cylinder (201a) and a disc (201b) disposed at both ends of the cylinder (201a). The disc (201b) has an annular groove (201c) on the side near the cylinder (201a). A ring (201d) is rotatably mounted on the annular groove (201c) and the ring (201d) is fixedly connected to the end of the cylinder (201a).

6. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 5, characterized in that: The base (101) is fixedly connected to both sides of a fixed seat (203). A second electric push rod (204) is fixedly installed on the fixed seat (203). A support seat (205) is fixedly installed on the telescopic end of the second electric push rod (204). A support frame (206) is fixedly connected on the support seat (205). Multiple air guide pipes (207) are fixedly connected on the support frame (206), and the air guide pipes (207) pass through the disc (201b).

7. The high-precision stretching equipment for unidirectional stretching of polyethylene film according to claim 1, characterized in that: The heating assembly (202) includes a heating rod (202a) disposed inside the cylinder (201a), a third electric push rod (202b) fixedly mounted on the support base (205), a guide frame (202c) fixedly connected to the telescopic end of the third electric push rod (202b), a connector (202d) slidably inserted in the guide frame (202c), and the connector (202d) fixedly connected to the heating rod (202a), and an oblique groove (201e) is provided on the disc (201b), and the connector (202d) is slidably inserted in the oblique groove (201e).

8. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 1, characterized in that: The base (101) is provided with a cooling roller (400) for rapidly cooling the polyethylene film. The cooling roller (400) is located on the side of the rolling unit (200) away from the preheating unit (300). Supports (401) are fixedly connected to both sides of the cooling roller (400), and the supports (401) are fixedly connected to the support base (205).

9. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 6, characterized in that: Multiple guide grooves (208) are provided on both sides of the machine base (101) and below the roller pressing unit (200). A limiting rod (209) is slidably inserted in the guide groove (208) and is fixedly connected to the support base (205).

10. The high-precision stretching equipment for unidirectional stretching and guiding of polyethylene film according to claim 1, characterized in that: The monitoring component (301) includes a positioning frame (301a) fixedly installed above the conveying platform (102). Multiple sensors for measuring the thickness of polyethylene film are equidistantly arranged on the bottom surface of the positioning frame (301a) near the conveying platform (102), and the sensors are electrically connected to the first electric push rod (303m) and the third electric push rod (202b).

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