Extrusion barrel heating structure and method with u-shaped outer channel

Abstract

The application discloses an extrusion cylinder heating structure and method with a U-shaped outer groove, and the heating structure comprises an extrusion cylinder body and a heating assembly. The extrusion cylinder body comprises an inner liner and an outer cylinder which are coaxially nested, and the inner liner is interference-fitted to the outer cylinder. The heating assembly comprises a plurality of electric heating pipes and a fixing structure for mounting the electric heating pipes. The fixing structure comprises a U-shaped outer groove which is matched with the plurality of electric heating pipes, arranged on the outer wall of the inner liner and extends along the axial direction of the extrusion cylinder body. The U-shaped outer groove is spaced apart on the outer wall of the inner liner, and a plurality of temperature measuring points are arranged in the groove along the axial direction. The U-shaped outer groove is used to replace the traditional axial deep hole to realize simple processing and high precision. The inner liner is directly heated to improve the heating efficiency, and the adverse effects of annealing and high-temperature creep caused by local overheating of the extrusion cylinder are avoided. The interference stability of the inner liner and the outer cylinder is maintained for a long time, and axial or radial deep holes do not need to be formed on the extrusion cylinder, so that the overall reliability and service life of the extrusion cylinder are improved.

Description

Technical Field

[0001] This invention relates to the technical field of extrusion molding processes, specifically to a heating structure and method for an extrusion cylinder with a U-shaped outer groove. Background Technology

[0002] Heating the extrusion cylinder used in aluminum-magnesium profile extrusion is a crucial step in ensuring extrusion quality. Traditional methods primarily employ C-shaped resistance wires or annular regenerating tubes for heating, which suffers from low efficiency, high energy consumption, uneven heating, poor temperature control, and environmental noise, making it difficult to achieve isothermal extrusion. Currently, resistance heating and induction heating are gradually being replaced by electric heating tubes. Electric heating tubes can be directly inserted into the deep holes of the outer cylinder of the extrusion cylinder, significantly improving heat transfer efficiency due to their proximity to the inner lining, and are now widely used.

[0003] However, existing technologies still face multiple bottlenecks, including high processing difficulty, high-temperature creep leading to interference fit degradation, low heating efficiency, and inability to precisely control temperature. The heating holes in the extrusion cylinder are mostly ultra-deep holes with a length-to-diameter ratio exceeding 30. The hole diameter limitation results in poor tool rigidity, making it prone to vibration, ripples, and taper during processing. Chip removal is difficult, and heat dissipation is poor. Hole straightness and surface quality are also difficult to detect and control. The outer cylinder and inner liner of the extrusion cylinder are made of high-quality mold steel, which has poor machinability. To facilitate the installation and removal of the heating element, a large gap must be reserved between the heating hole and the heating element, which reduces heat transfer efficiency and poses a risk of localized overheating and annealing of the extrusion cylinder. Furthermore, surface defects in deep holes can easily become fatigue crack initiation points. Simultaneously, long-term localized high temperatures during outer cylinder heating cause creep, which degrades the interference fit and weakens the load-bearing capacity of the inner liner. In addition, opening a large number of radial deep holes in the outer cylinder to arrange temperature measuring points will exacerbate stress concentration and shorten the extrusion cylinder life. Therefore, usually only one temperature measuring point is arranged for each independent heating zone, which cannot effectively cover the actual working conditions of many electric heating tubes. It is easy to miss overheating faults, causing the extrusion cylinder to undergo high-temperature annealing or local creep, affecting the overall reliability and service life of the extrusion cylinder. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a heating structure and method for an extrusion cylinder with a U-shaped outer groove, which solves the problems of high processing difficulty, low heating efficiency, high-temperature creep leading to interference fit deterioration, and small temperature measurement point coverage in existing heating structures.

[0005] According to a first aspect of the present invention, a heating structure for an extrusion cylinder with a U-shaped outer groove includes: The extrusion cylinder body includes a coaxially nested inner liner and an outer cylinder, wherein the inner liner is interference-fitted to the outer cylinder; A heating assembly, comprising a plurality of heating tubes and a fixing structure for mounting the plurality of heating tubes, the fixing structure comprising a plurality of U-shaped outer grooves that match the plurality of heating tubes, the plurality of U-shaped outer grooves being disposed on the outer wall of the liner and extending along the axial direction of the extrusion cylinder body, the plurality of U-shaped outer grooves being spaced apart on the outer wall of the liner; A temperature measuring component is used to monitor the temperature of the extrusion cylinder body in real time.

[0006] A heating structure for an extrusion cylinder with a U-shaped outer groove according to an embodiment of the present invention has at least the following beneficial effects: This invention replaces the axial deep hole in the outer cylinder of the prior art with a U-shaped outer groove structure located on the outer wall of the inner liner. This simplifies processing, allows for monitoring of the process, and improves precision, preventing fatigue cracks that could affect the service life of the extrusion cylinder. Furthermore, because multiple heating elements are located on the outer wall of the inner liner, the heating efficiency is higher compared to the heating structure located on the outer cylinder. This also avoids high-temperature creep caused by excessively high local temperatures, which could lead to interference fit deterioration. Moreover, this invention eliminates the need for radial deep holes and multiple temperature measuring points on a single U-shaped outer groove, allowing for the installation of a sufficient number of temperature measuring components to monitor the actual temperature distribution within the extrusion cylinder liner and to precisely and independently control the heating power of the heating elements.

[0007] According to some embodiments of the present invention, the temperature measuring assembly includes a plurality of temperature measuring elements, which are disposed within a plurality of U-shaped outer grooves.

[0008] According to some embodiments of the present invention, the open end of the U-shaped outer groove is provided with a transition portion that gradually expands outward smoothly on both sides, and a gap is formed between the transition portion and the heating tube, through which the temperature measuring element is inserted into the U-shaped outer groove.

[0009] According to some embodiments of the present invention, the U-shaped outer groove is provided with a first temperature measuring point, the first temperature measuring point is located in the middle of the U-shaped outer groove, and the temperature measuring element is inserted into the middle of the U-shaped outer groove to monitor the temperature of the first temperature measuring point in real time.

[0010] According to some embodiments of the present invention, the U-shaped outer groove is further provided with a second temperature measuring point and a third temperature measuring point, which are respectively located at the inlet end and the outlet end of the U-shaped outer groove near the extrusion cylinder body along the axial direction of the U-shaped outer groove.

[0011] According to the second aspect of the present invention, a heating method for an extrusion cylinder with a U-shaped outer groove is applicable to the above-described extrusion cylinder heating structure, the method comprising: The inner liner and the outer cylinder are prepared, wherein the outer wall of the inner liner is provided with a plurality of the aforementioned U-shaped outer grooves; The outer cylinder and the inner liner are interference-fitted together. The multiple heating elements are inserted into the multiple U-shaped outer grooves for fixation; The temperature measuring components are inserted into multiple U-shaped external grooves for fixation; The electric heating element heats the extrusion cylinder body according to the set power; Temperature data is obtained by measuring multiple temperature points, and the power of each heating element is independently adjusted.

[0012] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 A front view of an embodiment of a heating structure for an extrusion cylinder with a U-shaped outer groove provided by the present invention; Figure 2 for Figure 1 A partial schematic diagram of region A in an extrusion cylinder heating structure with a U-shaped outer groove, as shown; Figure 3 A cross-sectional view of an embodiment of a heating structure for an extrusion cylinder with a U-shaped outer groove provided by the present invention; Figure 4 This is a schematic flowchart of an embodiment of the extrusion cylinder heating structure and method with a U-shaped outer groove provided by the present invention.

[0014] Icon labels: Extrusion cylinder body 100; inner liner 110; outer cylinder 120; Heating component 200; heating element 210; U-shaped outer groove 220; transition section 221; temperature measuring element 230; first temperature measuring point 231; second temperature measuring point 232; third temperature measuring point 233. Detailed Implementation

[0015] Embodiments of the present invention are described in detail below. Examples of these 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 the present invention, and should not be construed as limiting the present invention.

[0016] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0017] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0018] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0020] Heating the extrusion cylinder for aluminum-magnesium profiles is a crucial step in ensuring extrusion quality. Traditional methods primarily use C-shaped resistance wires or annular regenerating tubes surrounding the cylinder for heating, which suffers from low efficiency, high energy consumption, uneven heating, temperature control issues, and environmental noise, making it difficult to achieve isothermal extrusion. With technological advancements, resistance heating and induction heating are gradually being replaced by electric heating tubes. These electric heating tubes can be directly inserted into a 120mm bore in the outer cylinder of the extrusion cylinder and are currently widely used.

[0021] However, existing technologies still face multiple bottlenecks, including high processing difficulty, interference fit degradation due to high-temperature creep, low heating efficiency, and inability to precisely control temperature. The heating holes in the extrusion cylinder are mostly ultra-deep holes with a length-to-diameter ratio exceeding 30. The hole diameter limitation results in poor tool rigidity, making it prone to vibration, ripples, and taper during processing. Chip removal is difficult, and heat dissipation is poor. Hole straightness and surface quality are also difficult to detect and control. Because the outer cylinder 120 and inner liner 110 of the extrusion cylinder are made of high-quality mold steel, their machinability is poor. To facilitate the installation and removal of the heating element, a large gap must be reserved between the heating hole and the heating element 210, which reduces heat transfer efficiency and poses a risk of localized overheating and annealing. Furthermore, surface defects in deep holes can easily become fatigue crack initiation points. Simultaneously, long-term localized high-temperature creep during heating of the outer cylinder 120 deteriorates the interference fit, weakening the load-bearing capacity of the inner liner 110. Furthermore, if a large number of radial deep holes are opened in the outer cylinder 120 to arrange temperature measuring points, it will exacerbate stress concentration and shorten the life of the outer cylinder 120. Therefore, usually only one temperature measuring point is arranged for each independent heating zone, which cannot effectively cover the actual working conditions of many electric heating tubes. It is easy to miss overheating faults, causing the extrusion cylinder to undergo high-temperature annealing or local creep, affecting the overall reliability and service life of the extrusion cylinder.

[0022] To address the aforementioned problems, this invention provides a heating structure and method for an extrusion cylinder with a U-shaped outer groove, which can effectively solve the problems of high processing difficulty, low heating efficiency, and interference fit deterioration caused by high-temperature creep in existing heating structures.

[0023] refer to Figures 1 to 4 The present invention provides a heating structure and method for an extrusion cylinder with a U-shaped outer groove, which are embodied in the following embodiments: Reference Figure 1 , Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a heating structure for an extrusion cylinder with a U-shaped outer groove, specifically including an extrusion cylinder body 100 and a heating component 200.

[0024] Reference Figure 1 As shown, the extrusion cylinder body 100 includes a coaxially nested inner liner 110 and an outer cylinder 120. The outer cylinder 120 is interference-fitted to the inner liner 110. The extrusion cylinder body 100 generates radial pre-compression stress through interference fit, which improves the load-bearing capacity of the inner cylinder, suppresses the plastic deformation of the inner liner 110 under high temperature and high pressure, and improves the thermal stress distribution and extends the service life.

[0025] The heating assembly 200 includes a plurality of heating tubes 210 and a fixing structure for mounting the plurality of heating tubes 210. The fixing structure includes a plurality of U-shaped outer grooves 220 that match the plurality of heating tubes 210. The plurality of U-shaped outer grooves 220 are disposed on the outer wall of the liner 110 and extend along the axial direction of the extrusion cylinder body 100. The plurality of U-shaped outer grooves 220 are spaced apart on the outer wall of the liner.

[0026] This invention replaces the traditional axial deep hole with multiple U-shaped outer grooves 220 on the outer wall of the inner liner 110. Since the U-shaped outer grooves 220 are external grooves, they are easy to process. Furthermore, the processing is visible, and the finished product can be measured and repaired, allowing for high-precision machining. This results in smooth, tool-scar-free groove walls with high straightness and precise groove shape. Smooth groove walls are less prone to fatigue cracks, which helps extend the service life of the extrusion cylinder. High straightness reduces resistance when inserting and removing the heating element 210 within the U-shaped outer grooves 220, facilitating assembly and disassembly. Precise groove shape reduces the gap between the inner wall of the outer cylinder 120, the wall of the U-shaped outer groove 220, and the heating element 210, reducing thermal resistance and improving heating efficiency.

[0027] Meanwhile, in the prior art, the heating element 210 is distributed inside the outer cylinder 120. In the present invention, the heating element 210 is located in the inner lining 110. On the one hand, it is closer to the center of the inner lining 110, which is conducive to rapid heating and improves heating efficiency. On the other hand, the temperature of the outer cylinder 120 is reduced, which can effectively avoid the adverse effects of high temperature creep in the outer cylinder 120, maintain the long-term interference stability of the inner lining 110 and the outer cylinder 120, and improve the overall reliability and service life of the extrusion cylinder.

[0028] Furthermore, this embodiment of the invention also includes a temperature measuring component for real-time temperature monitoring of the extrusion cylinder body 100, thereby providing a benchmark for precise temperature control of each zone.

[0029] The temperature measuring assembly includes multiple temperature measuring elements 230, which are located in multiple U-shaped outer grooves 220. The temperature of each of the multiple U-shaped outer grooves 220 is monitored in real time, and the local temperature of each position in the circumferential direction of the extrusion cylinder body 100 is measured independently. The power of multiple heating tubes 210 is controlled according to the temperature measured by the multiple temperature measuring elements 230, so as to make the extrusion cylinder body 100 heated evenly in the circumferential direction.

[0030] Specifically, regarding the installation location of the temperature sensing element 230, refer to... Figure 2 As shown, the open end of the U-shaped outer groove 220 has transition portions 221 that gradually expand outwards smoothly on both sides. A gap is formed between the transition portions 221 and the heating element 210. The temperature sensing element 230 is inserted into the U-shaped outer groove 220 through the gap. Figure 2 Taking the U-shaped outer groove 220 set on the outer wall of the inner liner 110 as an example, in this embodiment of the invention, the bottom of the U-shaped outer groove 220 is semi-circular, the side wall of the U-shaped outer groove 220 is tangent to the semi-circle, and the side wall and the outer wall of the inner liner 110 are rounded, so that the open end of the U-shaped outer groove 220 is provided with a transition portion 221 that gradually expands outward. The transition portion 221 forms a gap with the outer wall of the heating tube 210 and the inner wall of the outer cylinder 120 for the insertion of the temperature measuring element 230. By adjusting the insertion depth of the temperature measuring element 230, the temperature at different positions in the axial direction of the extrusion cylinder body 100 can be monitored, further mitigating or avoiding the adverse effects of high temperature creep, maintaining the long-term interference stability of the inner cylinder and the outer cylinder 120, avoiding overheating and local annealing of the extrusion cylinder, improving the overall reliability and service life of the extrusion cylinder. By setting the temperature measuring element 230 to be inserted along the gap, there is no need to process a radial deep hole for temperature measurement, which helps to reduce the processing difficulty and avoid stress concentration leading to the risk of fracture.

[0031] Reference Figure 3 As shown, according to some embodiments of the present invention, the U-shaped outer groove 220 is provided with a first temperature measuring point 231, which is located in the middle of the U-shaped outer groove 220. The temperature measuring element 230 is inserted into the middle of the U-shaped outer groove 220 to monitor the temperature of the outer groove in real time at the first temperature measuring point 231.

[0032] According to some embodiments of the present invention, the U-shaped outer groove 220 is further provided with a second temperature measuring point 232 and a third temperature measuring point 233. The second temperature measuring point 232 and the third temperature measuring point 233 are respectively located at both ends of the U-shaped outer groove 220 along the axial direction. By independently measuring the temperature of the first temperature measuring point 231, the second temperature measuring point 232 and the third temperature measuring point 233, the temperature of each position of the extrusion cylinder body 100 can be further accurately monitored, improving the temperature control accuracy. By setting up numerous temperature measuring points and controlling the temperature system, a uniform temperature field can be achieved, which can mitigate or avoid the adverse effects of high-temperature creep to a greater extent, maintain the long-term interference stability of the inner cylinder and the outer cylinder 120, avoid overheating and local annealing of the extrusion cylinder, improve the overall reliability and service life of the extrusion cylinder, and since multiple temperature measuring points are measured by inserting the temperature measuring element 230 through the gap, no additional channels need to be processed while increasing the number of temperature measuring points, which is beneficial to reducing manufacturing costs and avoiding stress concentration caused by too many channels, which can lead to the breakage of the extrusion cylinder body 100.

[0033] Reference Figure 4 As shown, the present invention also provides a heating method for an extrusion cylinder with a U-shaped outer groove, applicable to the above-mentioned heating structure of an extrusion cylinder with a U-shaped outer groove, the method comprising: Step S100: Prepare the inner liner 110 and the outer cylinder 120, wherein the outer wall of the inner liner 110 is provided with a plurality of U-shaped outer grooves 220; Step S200: Interference fit the outer cylinder 120 and the inner liner 110; Step S300: Insert multiple heating elements 210 into multiple U-shaped outer grooves 220 for fixation; Step S400: Insert the temperature measuring component into multiple U-shaped external slots 220 for fixation; Step S500: The heating element 210 heats the extrusion cylinder body according to the set power; Step S600: Temperature data is obtained by measuring multiple temperature measurement points, and the power of each heating element 210 is independently adjusted.

[0034] In step S100, the inner liner 110 and the outer cylinder 120 are first prepared. The inner liner 110 is made of high-quality mold steel to ensure its load-bearing capacity under high temperature and high pressure extrusion conditions, while the outer cylinder 120 is made of a material with relatively moderate mechanical properties and easy machining. Multiple U-shaped outer grooves 220 are machined along the axial direction of the extrusion cylinder body 100 on the outer wall of the inner liner 110, with the U-shaped outer grooves 220 spaced apart from each other on the outer wall of the inner liner. Because the U-shaped outer grooves 220 are external groove structures, the cutting state of the tool is visible and controllable during machining, chip removal is smooth, and heat dissipation is good. High-precision machining can be achieved without the use of special deep hole machining equipment, and the groove walls can achieve smoothness without tool marks, high straightness, and accurate groove shape. At the same time, the dimensions of the machined U-shaped outer grooves 220 can be directly measured and inspected, facilitating timely detection and correction of machining deviations, significantly reducing scrap rate and manufacturing costs.

[0035] In step S200, the machined inner liner 110 and outer cylinder 120 are coaxially nested and assembled, using an interference fit to ensure that the outer cylinder 120 tightly covers the outer side of the inner liner 110. The radial preload stress generated by the interference fit can effectively improve the load-bearing capacity of the inner liner 110, suppress its plastic deformation during high-temperature and high-pressure extrusion, and improve the thermal stress distribution to extend the service life of the structure. After the interference fit is installed, the U-shaped outer groove 220 and the inner wall of the outer cylinder 120 or the outer wall of the inner liner 110 together form a hole-shaped space for accommodating the heating element 210. This assembly method makes full use of the fact that the outer cylinder 120 is easier to machine than the inner liner 110, transforming the traditional problem of machining ultra-deep holes on the outer cylinder 120 into machining the outer groove of the inner liner 110, which not only ensures the fitting accuracy but also avoids problems such as insufficient tool rigidity, vibration, ripples, and taper deviation caused by deep hole machining.

[0036] In step S300, multiple heating elements 210 are inserted into the corresponding U-shaped outer grooves 220, forming a preset fitting gap between the outer wall of the heating element 210 and the wall of the U-shaped outer groove 220 and the inner wall of the outer cylinder 120. Because the U-shaped outer groove 220 has high machining precision and good straightness, the heating element 210 experiences less resistance during insertion and removal, facilitating assembly, disassembly, and maintenance. The gap between the wall of the U-shaped outer groove 220 and the inner wall of the outer cylinder 120, and between the heating element 210, can be significantly reduced, thereby effectively reducing contact thermal resistance, improving heat conduction efficiency, and avoiding the risk of localized overheating or even annealing of the heating element 210 and the extrusion cylinder body 100 due to excessively large gaps.

[0037] In step S400, the temperature measuring component is inserted into multiple U-shaped external slots 220 for fixation, thereby providing the basic conditions for real-time temperature measurement. In step S500, the heating element 210 is activated to heat the extrusion cylinder body 100 at a set power. Specifically, the heating element 210 directly heats the inner liner 110. Since the heating element 210 is located between the inner liner 110 and the outer cylinder 120, it is closer to the center of the inner liner 110 than the conventional heating method located in the outer cylinder 120, shortening the heat transfer path and significantly improving heating efficiency.

[0038] In step S600, during the heating process, the extrusion cylinder body 100 is monitored in real time by a temperature measuring component. The temperature measuring element 230 is inserted into the groove through the gap formed between the smoothly extended transition portion 221 on both sides of the open end of the U-shaped outer groove 220 and the heating tube 210, achieving temperature measurement without the need for additional radial deep holes to be machined on the outer cylinder 120. The temperature measuring point can be set in the middle of the U-shaped outer groove 220 to obtain a representative value close to the average temperature, or multiple independent monitoring points can be added at both ends of the outer groove. Based on the temperature data fed back from each temperature measuring point, the power of each heating tube 210 is independently adjusted to achieve uniform heating of the extrusion cylinder body 100 in the axial and circumferential directions, avoiding local overheating, thereby mitigating or avoiding the adverse effects of high-temperature creep on the interference fit, maintaining the long-term interference stability of the inner liner 110 and the outer cylinder 120, improving the overall reliability and service life of the extrusion cylinder, and repeating the measurement-feedback-temperature adjustment process until the temperature is maintained within the target range.

[0039] It is understood that the contents of the above-mentioned extrusion cylinder heating structure embodiment with U-shaped outer groove are all applicable to this method embodiment. The specific functions implemented by this method are the same as those of the above-mentioned heating structure embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned heating structure embodiment.

[0040] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0041] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A heating structure for an extrusion cylinder with a U-shaped outer groove, characterized in that, include: The extrusion cylinder body includes a coaxially nested inner liner and an outer cylinder, wherein the inner liner is interference-fitted to the outer cylinder; A heating assembly, comprising a plurality of heating tubes and a fixing structure for mounting the heating tubes, the fixing structure comprising a plurality of U-shaped outer grooves that match the plurality of heating tubes, the plurality of U-shaped outer grooves being disposed on the outer wall of the liner and extending along the axial direction of the extrusion cylinder body, the plurality of U-shaped outer grooves being spaced apart on the outer wall of the liner; A temperature measuring component is used to monitor the temperature of the extrusion cylinder body in real time.

2. The extrusion cylinder heating structure according to claim 1, characterized in that: The temperature measuring assembly includes multiple temperature measuring elements, which are disposed within multiple U-shaped outer grooves.

3. The extrusion cylinder heating structure according to claim 2, characterized in that: The open end of the U-shaped outer groove has a transition section that gradually expands outwards on both sides. A gap is formed between the transition section and the heating tube, and the temperature measuring element is inserted into the U-shaped outer groove through the gap.

4. The extrusion cylinder heating structure according to claim 3, characterized in that: The U-shaped outer groove is provided with a first temperature measuring point, which is located in the middle of the U-shaped outer groove. The temperature measuring element is inserted into the middle of the U-shaped outer groove to monitor the temperature of the first temperature measuring point in real time.

5. The extrusion cylinder heating structure according to claim 4, characterized in that: The U-shaped outer groove is also provided with a second temperature measuring point and a third temperature measuring point. The second temperature measuring point and the third temperature measuring point are respectively set at the inlet end and the outlet end near the extrusion cylinder body along the axial direction of the U-shaped outer groove.

6. A heating method for an extrusion cylinder with a U-shaped outer groove, characterized in that, The heating method, applicable to the extrusion cylinder heating structure as described in any one of claims 1 to 5, comprises: Prepare an inner liner and an outer cylinder, wherein the outer wall of the inner liner is provided with a plurality of the aforementioned U-shaped outer grooves; The outer cylinder and the inner liner are interference-fitted together. Multiple heating elements are inserted into multiple U-shaped outer grooves for fixation; The temperature measuring components are inserted into multiple U-shaped external grooves for fixation; The electric heating element heats the extrusion cylinder body according to the set power; Temperature data is obtained by measuring multiple temperature points, and the power of each heating element is independently adjusted.

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