A heat dissipation round pipe online forming equipment and process

Abstract

The present application relates to the field of heat dissipation round pipe processing, especially to a heat dissipation round pipe online forming equipment and process, the equipment comprises a bearing seat, the top of the bearing seat is provided with a roller assembly one for preliminarily U-shaped bending of aluminum strip raw material, a roller assembly two for secondary forming and closing bending of the bent material into a round pipe, and a shaping assembly for adopting an inner support and outer pressure method to round the side wall of the round pipe in combination with the roller assembly two, and the shaping assembly synchronously completes the processing of the internal thread groove of the round pipe; the present application adopts a two-stage progressive roller and inner support and outer pressure rounding structure to realize continuous high-precision rounding of aluminum strip, avoid deformation cracking, springback, excessive ovality and joint mispositioning, greatly improve the size consistency and structural strength, and simultaneously integrate synchronous thread spinning of the inner wall, chip fragmentation negative pressure collection and airflow self-cooling, so that the processing is damage-free, chip-free and heat deformation-free, and the product qualification rate and production line stability are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation tube processing, and more particularly to an online forming equipment and process for heat dissipation tubes. Background Technology

[0002] A heat dissipation tube is a tubular component made of aluminum strip through multi-stage roll forming and internal wall threading. The outer wall has a continuous closed circular cross section, and the inner wall is processed with spiral microgrooves. It achieves efficient heat dissipation by increasing the heat exchange area and enhancing turbulence. It is widely used in heat exchange systems such as refrigeration and energy storage.

[0003] Currently, in the traditional processing technology of heat dissipation tubes, in order to improve heat exchange efficiency, oblique indentations are usually pressed on one side of the aluminum strip using a toothed roller, and then the strip is continuously bent into a tube using multiple sets of bending rollers. However, during the bending process of the strip, the oblique indentations are subject to the superposition of roller pressure stress and bending tension, which easily causes tooth collapse and indentation distortion, forming irregular "egg flower" defects. This destroys the original design of the indentation's turbulence and expansion structure, directly weakening the expected heat dissipation performance of the tube. Meanwhile, due to the lack of effective internal wall support during the bending and forming stage, the aluminum strip is prone to local out-of-roundness or excessive ellipticity under the action of external rolling force, resulting in uneven gaps and excessive misalignment on the joint side of the round tube. This directly causes defects such as weld deviation, missed welds, and incomplete welds in the subsequent welding process, which seriously affects the weld formation quality and the structural strength of the round tube.

[0004] To address the aforementioned technical deficiencies, a solution is proposed that aims to simultaneously achieve high-precision forming of heat dissipation tubes, efficient inner wall processing, and stable and reliable production processes through internal and external collaborative molding and integrated online machining, thereby comprehensively improving product quality and production efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide an online forming equipment and process for heat dissipation circular tubes to solve the aforementioned technical defects.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: According to one aspect of the present invention, an online forming device for heat dissipation circular tubes is provided, including a support base, the top of which is provided with a first roller pressing component for initially U-shaped bending of aluminum strip raw material, a second roller pressing component for secondary forming and closing bending of the bent material into a circular tube, and a shaping component that combines the second roller pressing component to form the side wall of the circular tube by internal support and external pressure to achieve rounding, and the shaping component simultaneously completes the internal thread groove processing of the circular tube. The roller pressing assembly includes multiple sets of upper and lower convex rollers and grooved rollers that cooperate with each other. The second roller pressing assembly includes multiple sets of upper and lower cooperating concave pressing rollers and concave support rollers; The forming component includes an inner support rod extending between multiple sets of concave pressure rollers and concave support rollers. The inner support rod passes through the interior of the circular tube during the closed forming bending stage. Multiple threaded protrusions are integrally formed on the annular sidewall of the inner support rod in an annular array. Multiple chip guide grooves are provided on the sidewall of the inner support rod, and the chip guide grooves divide the threaded protrusions into multiple protrusion segments.

[0007] Preferably, the top of the support base is fixedly connected to mounting frame one and mounting frame two. The convex pressure roller and the grooved roller are rotatably mounted on mounting frame one, and the concave pressure roller and the concave support roller are rotatably mounted on mounting frame two. The top of the support base is equipped with an assembly drive component that drives the convex pressure roller, the grooved roller, the concave pressure roller and the concave support roller to rotate radially. The rotation direction of the convex pressure roller and the concave pressure roller is opposite to the rotation direction of the grooved roller and the concave support roller.

[0008] Preferably, the U-shaped bending radius of the multiple sets of convex pressure rollers and grooved rollers, as well as the closed bending radius of the multiple sets of concave pressure rollers and concave support rollers, all decrease gradually along the conveying direction of the circular tube, and the diameter of the inner support rod matches the inner diameter of the circular tube.

[0009] Preferably, a fixing frame is fixedly installed between the first mounting frame and the second mounting frame, and the annular sidewall of the inner support rod is provided with a mounting cavity and a chip suction cavity that are rotatably connected to the fixing frame. The chip suction cavity is connected to multiple chip guide grooves.

[0010] Preferably, an arc-shaped plate that is slidably connected to the inner support rod is fixedly connected to one side of the fixed frame and above the chip suction cavity. The width of the arc-shaped plate decreases continuously along the conveying direction of the circular tube, and the two sides of the arc-shaped plate slide in contact with the two sides of the U-shaped aluminum strip. A chip suction pipe communicating with the chip suction cavity is fixedly connected to the arc-shaped plate.

[0011] Preferably, the cross-sectional area of ​​the multiple protruding segments of each of the threaded protrusions gradually increases along the conveying direction of the circular tube, and a sliding blade extending to the chip suction cavity is fixedly connected to the bottom of the arc plate. The sliding blade slides against the inner wall of the chip suction cavity on one side of the chip guide groove.

[0012] Preferably, the annular sidewall of the inner support rod is provided with a toothed groove, a servo motor is mounted on the fixing frame by bolts, and a gear that meshes with the toothed groove is fixedly mounted on the output shaft of the servo motor.

[0013] One method for online forming of a heat dissipation circular tube includes the following steps: S1: Two-stage progressive bending internal support rounding forming: Aluminum strip is extruded into a U-shape through convex pressure rollers and grooved rollers, and then extruded into a round tube by concave pressure rollers and concave support rollers in conjunction with internal support rods using an internal support and external pressure method. S2: Rotary thread groove: The inner support rod rotates, and the thread ridge is composed of convex segments with gradually changing cross-sectional area, which rotary cuts the inner wall of the round tube to form a thread groove; S3: Chip Slitting, Collection, and Air Cooling: Chips generated by rotary cutting enter the chip guide groove and chip suction chamber, are sheared and broken by the slitting blade, and are discharged under negative pressure; the airflow simultaneously cools the threaded protrusions and the pipe wall to prevent high-temperature deformation.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention utilizes a composite structure of two-stage progressive roll forming and synchronous rounding with internal support and external pressure to achieve continuous high-precision forming of heat dissipation tubes from aluminum strip to finished tubes: First, multiple sets of convex and concave rollers gradually reduce the bending radius along the conveying direction, smoothly transitioning the aluminum strip into a U-shaped semi-finished product, avoiding stress concentration, cracking, and springback problems caused by single large deformation; then, multiple sets of concave rollers and concave support rollers continue to close and bend step by step, forming a two-way constraint rounding mechanism of external wall roll forming and internal wall support with the internal support rod extending into the tube, fundamentally solving common industry defects such as excessive ellipticity of tubes, misaligned joints, and local out-of-roundness; achieving a significant improvement in the overall dimensional consistency, cross-sectional roundness, and joint fit of the tube, resulting in smaller diameter tolerances and more stable structural strength, significantly improving the finished product qualification rate of heat dissipation tubes.

[0015] 2. This invention also integrates synchronous rotary cutting of inner wall thread grooves, automatic chip fragmentation and collection, and self-cooling of the cutting zone into one unit, achieving efficient and high-quality online processing: the threaded protrusions on the inner support rod with progressively larger cross-sections along the conveying direction rotate synchronously with the pipe conveying speed, and the heat dissipation thread groove is formed by using a progressive cutting depth method; and the chips generated by rotary cutting enter the chip suction chamber along the chip guide groove, and are sheared into fine chips by the slitting blade during rotation, which are quickly discharged outwards with the help of the negative pressure system, eliminating the problem of chip retention that scratches the inner wall and jams the equipment; at the same time, outside air enters the chip suction chamber through the pipe end and the chip guide groove to form an airflow channel, continuously cooling the threaded protrusions and the cutting position of the pipe wall while discharging chips, effectively avoiding the softening and deformation of the aluminum pipe caused by the heat generated by continuous cutting. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a partial structural schematic diagram of the first and second roller pressing components of the present invention; Figure 3 This is a schematic diagram showing the cooperation between the shaping component of the present invention and the concave pressure roller and the concave support roller; Figure 4 This is a schematic diagram of the structure of the shaping component of the present invention; Figure 5 This is a schematic diagram of the internal support rod of the present invention; Figure 6 This is a schematic diagram of the arc-shaped plate of the present invention; Figure 7 This is a schematic diagram of the structure of the inner support rod and inner support tube of the present invention; In the attached diagram, 1 is the support base; 11 is the assembly drive component; 2. Roller assembly one; 21. Convex roller; 22. Grooved roller; 23. Mounting frame one; 3. Roller assembly two; 31. Concave pressure roller; 32. Concave idler roller; 33. Mounting frame two; 4. Shaping component; 41. Inner support rod; 42. Threaded protrusion; 43. Chip guide groove; 44. Fixing bracket; 45. Mounting cavity; 46. Chip suction cavity; 47. Arc plate; 48. Chip suction pipe; 49. Slitting blade. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are merely to provide the reader with a thorough understanding of one or more aspects of the invention, and these aspects of the invention can be achieved even without these specific details.

[0018] Example 1: Please refer to Figures 1-4 As shown, the following solutions can be used to address the issues of poor roundness and misalignment of joints during the forming process of heat dissipation tubes. The heat dissipation circular tube online forming equipment in this embodiment includes a support seat 1, which provides stable support for the entire forming mechanism, ensuring that the rolling and forming process does not shake or shift, and improving the overall processing stability. The top of the support seat 1 is provided with a rolling component 1 2 for initial U-shaped bending of aluminum strip raw material, a rolling component 2 3 for secondary forming and closing bending of the bent material into a circular tube, and a shaping component 4 that combines the rolling component 2 3 to form the side wall of the circular tube by internal support and external pressure to form a round shape. The shaping component 4 also simultaneously completes the internal thread groove processing of the circular tube. The roll forming assembly 2 includes multiple sets of upper and lower convex rollers 21 and grooved rollers 22. The bending radius is gradually reduced along the conveying direction by multiple sets of convex rollers 21 and grooved rollers 22 to smoothly transition the aluminum strip into a U-shaped semi-finished product, avoiding stress concentration, cracking and springback problems caused by single large deformation. Roller assembly 2 3 includes multiple sets of upper and lower cooperating concave rollers 31 and concave support rollers 32; The shaping component 4 includes an inner support rod 41 extending between multiple sets of concave pressure rollers 31 and concave support rollers 32. The inner support rod 41 is inserted into the inside of the round tube during the closed forming and bending stage. Subsequently, the multiple sets of concave pressure rollers 31 and concave support rollers 32 continue to close and bend step by step. Together with the inner support rod 41 extending into the tube, a two-way constraint rounding mechanism of outer wall rolling and inner wall support is formed, which fundamentally solves common defects in the industry such as excessive ovality of the round tube, misalignment of joints, and local loss of roundness.

[0019] The top of the support 1 is fixedly connected to mounting bracket 1 23 and mounting bracket 2 33. Mounting bracket 1 23 and mounting bracket 2 33 ensure the accurate installation position of each roller, improve coaxiality and running accuracy. Convex roller 21 and groove roller 22 are rotatably mounted on mounting bracket 1 23, and concave roller 31 and concave support roller 32 are rotatably mounted on mounting bracket 2 33. The top of the support 1 is equipped with an assembly drive component 11 that drives the radial rotation of convex roller 21, groove roller 22, concave roller 31 and concave support roller 32. The rotation direction of convex roller 21 and concave roller 31 is opposite to the rotation direction of groove roller 22 and concave support roller 32.

[0020] The U-shaped bending radius of multiple sets of convex pressure rollers 21 and grooved rollers 22, as well as the closed bending radius of multiple sets of concave pressure rollers 31 and concave support rollers 32, are gradually reduced along the conveying direction of the circular tube. The gradual diameter change bending disperses the deformation and avoids stress concentration, cracking and springback. The diameter of the inner support rod 41 matches the inner diameter of the circular tube. The matching inner diameter ensures high support fit and more accurate rounding effect.

[0021] Example 2: Please refer to Figures 4-7 As shown, the problem of easy damage during the machining of the inner wall threads of the heat dissipation tube can be solved by the following solutions; In this embodiment, multiple threaded protrusions 42 are integrally formed on the annular sidewall of the inner support rod 41 in an annular array. The threaded protrusions 42 are used to spin-cut the inner wall to form heat dissipation grooves. The integral structure has high strength and is not easily deformed. Multiple sets of concave pressure rollers 31 and concave support rollers 32 cooperate to perform preliminary step-by-step extrusion and bending of the U-shaped aluminum strip into a formed round tube. During the extrusion process, the inner support rod 41 performs internal support and rounding of the inner wall of the formed round tube, and multiple sets of threaded protrusions 42 are extruded onto the inner wall of the round tube. Multiple chip guide grooves 43 are provided on the side wall of the inner support rod 41. The chip guide grooves 43 divide the threaded protrusion 42 into multiple protrusion segments. The chip guide grooves 43 promptly guide the chips. The graded structure of the protrusion segments realizes progressive cutting and reduces damage to the inner wall. The inner support rod 41 rotates to perform thread groove cutting on the inner wall of the round tube.

[0022] A fixed frame 44 is fixedly installed between mounting frame 1 23 and mounting frame 2 33. The annular side wall of the inner support rod 41 is provided with a mounting cavity 45 and a chip suction cavity 46 that are rotatably connected to the fixed frame 44. The chip suction cavity 46 communicates with multiple chip guide grooves 43. The chip suction cavity 46 collects chips in a concentrated manner to avoid chips from accumulating and scratching the inner wall or jamming the equipment.

[0023] An arc-shaped plate 47, which is slidably connected to the inner support rod 41, is fixedly connected to one side of the fixed frame 44 and above the chip suction chamber 46. The arc-shaped plate 47, combined with the U-shaped bent aluminum strip, forms a complete chip suction chamber 46, which effectively collects chips. The width of the arc-shaped plate 47 continuously decreases along the conveying direction of the circular tube, and the two sides of the arc-shaped plate 47 slide in contact with the two sides of the U-shaped aluminum strip. The gradual width adapts to the gradual closing process of the strip, making the guidance smoother and preventing edge scraping. A chip suction pipe 48, which communicates with the chip suction chamber 46, is fixedly connected to the arc-shaped plate 47. The chip suction pipe 48 is connected to negative pressure to realize the rapid removal of chips and keep the inside of the pipe clean.

[0024] The cross-sectional area of ​​multiple protruding segments of each threaded protrusion 42 increases progressively along the conveying direction of the circular tube. The progressive increase in the protrusions achieves a gradual deepening of the cut, avoiding tearing or straining of the inner wall caused by a single cut. A slitting blade 49 extending to the chip suction cavity 46 is fixedly connected to the bottom of the arc plate 47. The slitting blade 49 and the chip suction cavity 46 slide against each other on one side of the inner wall of the chip guide groove 43. The end of the protruding segment spins and cuts the thread groove to generate a cutting strip. Through the contact between the inner support rod 41 and the inner wall of the circular tube, the generated cutting strip smoothly enters the chip guide groove 43 and then enters the chip suction cavity 46. The inner support rod 41 carries the circumferential rotation of the chip guide groove 43 and contacts the slitting blade 49 on the arc plate 47. Through the sliding contact between the slitting blade 49 and the side wall of the chip suction chamber 46, the slitting blade 49 and the end face of the chip guide groove 43 form a scissor structure to cut and break the cutting strip. The chip suction pipe 48 is connected to the external negative pressure collection device to collect the chips under negative pressure. The outside air enters the chip suction chamber 46 through the end face of the formed round tube and the chip guide groove 43. During the air flow, the convex section and the inner wall of the round tube are cooled to avoid deformation of the round tube caused by continuous cutting heat.

[0025] The inner support rod 41 has a toothed groove on its annular sidewall. A servo motor is bolted to the fixing frame 44, and a gear that meshes with the toothed groove is fixedly installed on the output shaft of the servo motor. The servo motor precisely controls the rotation speed of the inner support rod 41, so that the rotary cutting speed matches the strip conveying speed, thus completely avoiding damage to the inner wall.

[0026] Example 3: Please refer to Figures 1-7 As shown, the present invention also proposes an online forming process for heat dissipation circular tubes, including the following steps: Step 1: Two-stage progressive bending and internal support rounding forming: The aluminum strip is extruded into a U-shape step by step by the convex roller 21 and the grooved roller 22, and then extruded into a round tube by the concave roller 31 and the concave support roller 32 in conjunction with the internal support rod 41 using an internal support and external pressure method; The aluminum strip is passed between multiple sets of upper and lower cooperating convex rollers 21 and grooved rollers 22 in sequence. The aluminum strip is initially extruded and bent into a U-shape by multiple sets of upper and lower cooperating convex rollers 21 and grooved rollers 22. Then it is passed between multiple sets of upper and lower cooperating concave rollers 31 and concave support rollers 32, and the internal support rod 41 is located inside the U-shaped aluminum strip. The U-shaped aluminum strip is initially extruded and bent into a round tube by multiple sets of concave rollers 31 and concave support rollers 32. During the extrusion process, the inner wall of the formed round tube is internally supported and rounded by the internal support rod 41, and multiple sets of threaded protrusions 42 are pressed onto the inner wall of the round tube; Step 2: Rotary Cutting of Thread Grooves: The inner support rod 41 rotates, forming threaded ridges 42 composed of convex segments with gradually changing cross-sectional areas, which rotary cuts the inner wall of the round tube to form threaded grooves; the assembly drive component 11 drives the convex pressure roller 21, groove roller 22, concave pressure roller 31 and concave support roller 32 to rotate radially, performing online continuous forming processing on the aluminum strip. During this process, the servo motor, combined with gears and tooth grooves, drives the inner support rod 41 to rotate. The multiple convex segments with successively increasing cross-sectional areas on each threaded ridge 42, combined with multiple sets of concave pressure rollers 31 and concave support rollers 32, clamp the outer wall of the round tube in the opposite direction, and perform threaded groove rotary cutting processing on the inner wall of the round tube. The displacement speed formed by the threaded groove and the rotating threaded ridge 42 is consistent with the displacement speed of the aluminum strip, avoiding the problem of additional damage to the inner wall of the formed round tube. Step 3: Chip Slitting, Collection, and Air Cooling: The chips generated by rotary cutting enter the chip guide groove 43 and the chip suction chamber 46. After being sheared and broken by the slitting blade 49, they are discharged under negative pressure. The airflow simultaneously cools the threaded protrusions 42 and the pipe wall to prevent high-temperature deformation. The end of the protrusion section spins and cuts the threaded groove to generate cutting strips. Through the contact between the inner support rod 41 and the inner wall of the round pipe, the generated chip strips smoothly enter the chip guide groove 43 and then enter the chip suction chamber 46. Then, combined with the circumferential rotation of the chip guide groove 43 carried by the inner support rod 41, the chips contact the inner wall of the pipe. The sliding blade 49 on the arc plate 47 slides against the side wall of the chip suction chamber 46, forming a scissor structure with the end face of the chip guide groove 43, which cuts and breaks down the cutting strip. The chip suction pipe 48 is connected to an external negative pressure collection device for negative pressure collection of chips. External air enters the chip suction chamber 46 through the end face of the formed round tube and the chip guide groove 43. During the air flow, the convex section and the inner wall of the round tube are cooled to avoid deformation of the round tube caused by continuous cutting heat.

[0027] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An online forming device for heat dissipation circular tubes, comprising a support base (1), characterized in that, The top of the bearing seat (1) is provided with a roller pressing assembly 1 (2) for initially U-shaped bending of aluminum strip material, a roller pressing assembly 2 (3) for secondary forming and closing bending of the bent material into a round tube, and a shaping assembly (4) for forming the round tube sidewall by using an internal support and external pressure method in conjunction with the roller pressing assembly 2 (3), and the shaping assembly (4) simultaneously completes the internal thread groove processing of the round tube. The roller pressing assembly (2) includes multiple sets of upper and lower convex rollers (21) and grooved rollers (22). The roller pressing assembly 2 (3) includes multiple sets of upper and lower cooperating concave pressing rollers (31) and concave support rollers (32). The top of the support base (1) is fixedly connected to the mounting frame one (23) and the mounting frame two (33). The convex pressure roller (21) and the grooved roller (22) are rotatably mounted on the mounting frame one (23), and the concave pressure roller (31) and the concave support roller (32) are rotatably mounted on the mounting frame two (33). The top of the support base (1) is equipped with an assembly drive assembly (11) that drives the convex pressure roller (21), the grooved roller (22), the concave pressure roller (31) and the concave support roller (32) to rotate radially. The rotation direction of the convex pressure roller (21) and the concave pressure roller (31) is opposite to the rotation direction of the grooved roller (22) and the concave support roller (32). The shaping component (4) includes an inner support rod (41) extending between multiple sets of concave pressure rollers (31) and concave support rollers (32). The inner support rod (41) is inserted into the inside of the round tube during the closed forming bending stage. Multiple threaded protrusions (42) are integrally formed on the annular sidewall of the inner support rod (41) and are arranged in an annular array. Multiple chip guide grooves (43) are provided on the sidewall of the inner support rod (41) and the chip guide grooves (43) divide the threaded protrusions (42) into multiple protrusion segments. The U-shaped bending radius of the multiple sets of convex pressure rollers (21) and grooved rollers (22), and the closed bending radius of the multiple sets of concave pressure rollers (31) and concave support rollers (32) are all gradually reduced along the conveying direction of the circular tube, and the diameter of the inner support rod (41) is matched with the inner diameter of the circular tube; A fixed frame (44) is fixedly installed between the first mounting frame (23) and the second mounting frame (33). The inner support rod (41) has an installation cavity (45) and a chip suction cavity (46) that are rotatably connected to the fixed frame (44) on its annular side wall. The chip suction cavity (46) is connected to multiple chip guide grooves (43). An arc-shaped plate (47) that is slidably connected to the inner support rod (41) is fixedly connected to one side of the fixed frame (44) and above the chip suction cavity (46). The width of the arc-shaped plate (47) continuously decreases along the conveying direction of the circular tube, and the two sides of the arc-shaped plate (47) slide in contact with the two sides of the U-shaped aluminum strip. A chip suction pipe (48) that communicates with the chip suction cavity (46) is fixedly connected to the arc-shaped plate (47).

2. The online forming equipment for heat dissipation circular tubes according to claim 1, characterized in that, The cross-sectional area of ​​the multiple protruding segments of each of the threaded protrusions (42) increases gradually along the conveying direction of the circular tube. The bottom of the arc plate (47) is fixedly connected to a sliding blade (49) extending to the chip suction cavity (46). The sliding blade (49) and the chip suction cavity (46) slide against each other on one side of the inner wall of the chip guide groove (43).

3. The online forming equipment for heat dissipation circular tubes according to claim 1, characterized in that, The inner support rod (41) has a toothed groove on its annular sidewall. A servo motor is mounted on the fixing frame (44) by bolts, and a gear that meshes with the toothed groove is fixedly mounted on the output shaft of the servo motor.

4. An online forming process for heat dissipation circular tubes, employing an online forming equipment for heat dissipation circular tubes as described in any one of claims 1-3, characterized in that, Includes the following steps: S1: Two-stage progressive bending inner support rounding forming: The aluminum strip is extruded into a U-shape step by step by the convex pressure roller (21) and the groove roller (22), and then extruded into a round tube by the concave pressure roller (31) and the concave support roller (32) in conjunction with the inner support rod (41) using the inner support and outer pressure method; S2: Rotary cutting of thread groove: The inner support rod (41) rotates and forms a thread ridge (42) composed of convex segments with gradually changing cross-sectional area, which rotary cuts the inner wall of the round tube to form a thread groove; S3: Chip cutting and collection and air cooling: Chips generated by rotary cutting enter the chip guide groove (43) and chip suction chamber (46), and are discharged under negative pressure after being sheared and broken by the cutting blade (49); the airflow simultaneously cools the threaded protrusions (42) and the pipe wall to prevent high temperature deformation.

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