Forming die and method for drawing and forming thin pipe fitting

Abstract

The invention discloses a forming die and method for drawing and forming thin pipe fittings, and relates to the technical field of drawing and forming thin pipe fittings, the forming die comprises an upper die and a lower die, the upper die comprises an upper support, an upper base plate and a fixing plate, and the upper base plate and the fixing plate are sequentially and fixedly arranged on the bottom surface of the upper support; a limiting plate and a discharging plate which are sequentially and fixedly arranged into a whole are arranged below the fixing plate, a second vertical spring is fixedly arranged in the upper support, a second force transmission column is fixedly arranged at the bottom end of the second vertical spring, and an extension male die downwards penetrating through the discharging plate is fixedly arranged on the bottom surface of the fixing rod piece. The lower die comprises a base, a lower base plate and a female die plate which are sequentially and fixedly arranged into a whole from bottom to top, a small hole located under the extending male die is formed in the female die insert, and a first vertical spring and a third vertical spring which are located on the two sides of the female die insert respectively are fixedly arranged in the base. The device has the beneficial effects that the working intensity of workers is greatly relieved, the forming efficiency of thin pipe fittings is greatly improved, and small-size blank pipes can be stretched.

Description

Technical Field

[0001] This invention relates to the technical field of drawing out thin tubular parts, and in particular to a forming mold and method for drawing out thin tubular parts. Background Technology

[0002] The structure of a certain produced material is as follows: Figures 1-3 As shown, it includes a long thin plate 1, on the bottom surface of the long thin plate 1, and at intervals along its length, multiple blank tubes 2 are integrally formed with the long thin plate 1. The bottom end of the blank tube 2 is closed, and the top end of the blank tube 2 is open to the outside. The total length of the blank tube 2 is 6.5 mm, its inner diameter is 1 mm, and its outer diameter is 1.2 mm. The process requires that each blank tube 2 on the long thin plate 1 be extended by 1.5 mm, that is, the total length of the blank tube 2 needs to be stretched from 6.5 mm to 8.0 mm to form a thin tubular fitting that can be supplied to the customer.

[0003] The method by which the workers in the workshop extend each of the blank tubes 2 on the long thin plate 1 by 1.5mm is as follows: Sa, the worker uses sleeve 3 to cover the lower end of the first blank tube 2, such as Figure 4 As shown; then the worker inserts the punch 4 into the inner hole of the blank tube 2 from top to bottom, as shown. Figures 5-6 As shown; Sb. The worker uses a wooden hammer to strike the top of the punch 4 in the following direction. Figure 6 As shown by the middle arrow, under the impact, the material around the blank tube 2 deforms downward, thereby extending the first blank tube 2 and forming the required thin tube. By repeating steps Sa to Sb multiple times, workers can extend each blank tube 2 on the long thin plate 1 downwards, thereby forming the required thin tubes.

[0004] However, although the method used in the workshop can extend downwards for each blank tube 2, it still has the following technical defects: In step Sa, because the blank tube 2 is quite small, the worker cannot put the sleeve 3 on the outside of the blank tube 2 in one go. Instead, multiple fitting operations are required to put the sleeve 3 on the outside of the blank tube 2. In step Sb, the worker also has to manually use a wooden hammer to strike the top of the punch 4 to complete the extension of the blank tube 2 and then form the thin tube. The whole operation is done manually by the worker, which not only increases the worker's workload but also reduces the forming efficiency of the thin tube.

[0005] Therefore, there is an urgent need for a molding die and method that can greatly reduce the workload of workers and greatly improve the forming efficiency of thin tubes. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a forming mold and method for drawing out thin tubes, which greatly reduces the labor intensity of workers and greatly improves the forming efficiency of thin tubes.

[0007] The objective of this invention is achieved through the following technical solution: A forming mold for drawing out thin tubular parts, comprising an upper mold and a lower mold. The upper mold includes an upper support, an upper pad plate and a fixing plate sequentially fixed on the bottom surface of the upper support. A limiting plate and a stripping plate sequentially fixed together are provided below the fixing plate. A gap H is left between the top surface of the limiting plate and the bottom surface of the fixing plate. A second vertical spring is fixed inside the upper support. A second force transmission column is fixed at the bottom end of the second vertical spring. The second force transmission column passes downward through the upper support, the upper pad plate, the fixing plate, and the gap H sequentially and is fixed on the limiting plate. A fixing rod is fixed on the bottom surface of the upper pad plate, passing downward through the fixing plate, the gap H, and the limiting plate sequentially and extending into the stripping plate. An extending punch that passes downward through the stripping plate is fixed on the bottom surface of the fixing rod. The lower mold includes a base, a lower pad, and a concave template, which are fixed together from bottom to top. A concave mold insert is fixed inside the concave template. The top surface of the concave mold insert is flush with the top surface of the concave template. A small hole is opened in the concave mold insert located directly below the extending punch. A first vertical spring and a third vertical spring are fixed inside the base, located on both sides of the concave mold insert. The first vertical spring and the third vertical spring are respectively fixed on the top surface of the first force transmission column and the third force transmission column. The first force transmission column and the third force transmission column both penetrate upward through the lower pad plate and the concave template and extend outside the concave template. The distance between the top surface of the first force transmission column and the top surface of the concave template is greater than the distance between the top surface of the third force transmission column and the top surface of the concave template. The spring force of the third vertical spring is greater than that of the second vertical spring, and the spring force of the second vertical spring is greater than that of the first vertical spring.

[0008] The upper support of the upper die is fixed to the stamping head of the stamping machine.

[0009] The diameter of the extending punch is equal to the inner diameter of the blank tube.

[0010] The extending punch is coaxially arranged with the fixed rod.

[0011] A guide hole is provided between the limiting plate and the unloading plate, and the fixing rod is slidably engaged with the guide hole.

[0012] The diameter of the small hole in the die insert is equal to the outer diameter of the blank tube.

[0013] The third force transmission column is located directly below the second force transmission column.

[0014] A method for drawing and forming a thin tube includes the following steps: S1. The strip material is pulled from back to front into the area enclosed by the strip plate and the die plate by the pulling mechanism, and the first blank tube of the long strip of material is initially positioned directly below the drawing punch. S2. Control the punch head of the press to move downward. The punch head drives the upper support to move downward. The upper support drives the upper pad, the fixed plate, the extending punch, the second vertical spring, and the second force transmission column to move downward synchronously. The second force transmission column drives the limiting plate and the stripper plate to move downward synchronously. The extending punch moves toward the inner hole of the first blank tube, while the stripper plate moves toward the long thin plate. S3. As the punch head of the press continues to move downward, the extension punch is initially inserted into the inner hole of the blank tube to guide the blank tube. At the same time, the stripper plate presses the long strip of thin plate onto the top surface of the first force transmission column. S4. As the punch head of the press continues to move downward, the punch head drives the upper support to continue moving downward. The upper support drives the upper pad, the fixed plate, the extending punch, the second vertical spring, and the second force transmission column to move downward synchronously. The second force transmission column drives the limiting plate and the stripper plate to move downward synchronously. Since the spring force of the second vertical spring is greater than that of the first vertical spring, the stripper plate presses down on the long strip plate to make it move downward. The long strip plate then drives the blank tube to move towards the small hole of the die insert. At the same time, the long strip plate also presses down on the first force transmission column to make it move downward. The first force transmission column compresses the first vertical spring downward. When the long strip plate is blocked by the third force transmission column, the lower end of the blank tube is inserted into the small hole of the die insert to cover the lower end of the blank tube. At the same time, because the spring force of the third vertical spring is greater than that of the second vertical spring, the stripper plate cannot continue to move downward. Meanwhile, the strip is clamped and fixed between the stripper plate, the first force transmission column and the third force transmission column. S5. As the punch head of the press continues to move downward, the punch head drives the upper support to continue moving downward. The upper support drives the upper pad, the fixed plate, and the extending punch to move downward relative to the stationary limit plate and the stripper plate. Meanwhile, the second force transmission column compresses the second vertical spring upward. At the same time, the gap H between the fixed plate and the limit plate gradually decreases. Simultaneously, the extending punch continues to extend downward into the inner hole of the blank tube. When the gap H between the fixed plate and the limit plate decreases to 1.5mm, the extending punch is just completely in contact with the inner hole of the blank tube. At this time, the extending punch is in the extending position. S6. As the punch head of the press continues to move downward, the punch head drives the upper support to continue moving downward. The upper support drives the upper pad, the fixed plate, and the extending punch to continue moving downward relative to the stationary limiting plate and the stripper plate. The extending punch presses down on the bottom closed end of the blank tube, and gradually extends the blank tube downward. At the same time, the gap H between the fixed plate and the limiting plate gradually decreases. When the bottom surface of the fixed plate just presses against the top surface of the limiting plate, the extending punch extends the blank tube downward by 1.5mm, thus forming a thin tube with a total length of 8mm. S7. After forming, control the punch head of the press to return to the upward position. The punch head drives the upper support to move upward. The upper support drives the upper pad, the fixed plate, the extension punch, the second vertical spring, and the second force transmission column to move upward synchronously. Under the elastic restoring force of the second vertical spring, the second force transmission column returns to the position. Subsequently, under the elastic restoring force of the first vertical spring, the first force transmission column returns to the position. S8. The worker repeats steps S1 to S7 multiple times to extend each blank tube on the long thin plate downwards, thereby forming the corresponding thin tubes of the required length.

[0015] The present invention has the following advantages: it greatly reduces the labor intensity of workers and greatly improves the forming efficiency of thin tubes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the material-supported structure; Figure 2 for Figure 1 AA section view; Figure 3 for Figure 2 A magnified view of part B; Figure 4 A schematic diagram showing a worker using a sleeve to cover the lower end of the first blank tube; Figure 5 This is a diagram showing a worker inserting a punch into the inner hole of a blank tube from top to bottom. Figure 6 for Figure 5 Enlarged view of part C; Figure 7 This is a schematic diagram of the structure of the present invention; Figure 8 This is a schematic diagram showing the connection between the fixed rod and the extending punch; Figure 9 This is a schematic diagram of the unloading plate structure; Figure 10 This is a schematic diagram of the structure of the die insert; Figure 11 A schematic diagram for initially positioning the first blank tube of the long strip of sheet material directly below the drawing punch; Figure 12This is a schematic diagram illustrating the initial insertion of the punch into the inner hole of the blank tube. Figure 13 for Figure 12 Enlarged view of part D; Figure 14 This is a schematic diagram showing the lower end of the blank tube being inserted into the small hole of the die insert. Figure 15 for Figure 14 Enlarged view of part E; Figure 16 This is a schematic diagram illustrating the complete fit between the punch and the inner hole of the blank tube. Figure 17 for Figure 16 A magnified view of part F; In the picture: 1-Long thin plate, 2-Blank tube, 3-Sleeve, 4-Punch; 5-Upper support, 6-Upper pad, 7-Fixing plate, 8-Limiting plate, 9-Unloading plate, 10-Gap H, 11-Second vertical spring, 12-Second force transmission column, 13-Fixing rod, 14-Extending punch; 15-Base, 16-Lower pad, 17-Diamond template, 18-Diamond insert, 19-Small hole, 20-First vertical spring, 21-Third vertical spring, 22-First force transmission column, 23-Third force transmission column, 24-Guide hole. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description: like Figures 7-10 As shown, a forming mold for drawing out thin tubular parts includes an upper mold and a lower mold. The upper mold includes an upper support 5, an upper pad 6 and a fixing plate 7 sequentially fixed to the bottom surface of the upper support 5. A limiting plate 8 and a stripping plate 9 sequentially fixed together are arranged below the fixing plate 7. A gap H10 is left between the top surface of the limiting plate 8 and the bottom surface of the fixing plate 7. A second vertical spring 11 is fixed inside the upper support 5. A second force transmission column 12 is fixed at the bottom end of the second vertical spring 11. 12 passes downwards sequentially through the upper support 5, upper pad 6, fixing plate 7, and gap H10, and is fixed to the limiting plate 8. A fixing rod 13 is fixed on the bottom surface of the upper pad 6, passing downwards sequentially through the fixing plate 7, gap H10, and limiting plate 8, and extending into the unloading plate 9. An extending punch 14, passing downwards through the unloading plate 9, is fixed on the bottom surface of the fixing rod 13. The extending punch 14 is coaxially arranged with the fixing rod 13, and the diameter of the extending punch 14 is equal to the inner diameter of the blank tube 2. The upper support 5 of the upper die is fixed to the stamping head of the stamping machine.

[0018] The lower mold includes a base 15, a lower pad 16, and a concave template 17, which are fixed together from bottom to top. A concave template 17 has a concave mold insert 18 fixed inside. The top surface of the concave mold insert 18 is flush with the top surface of the concave template 17. A small hole 19 is opened in the concave mold insert 18, located directly below the extending punch 14. A first vertical spring 20 and a third vertical spring 21 are fixed inside the base 15, located on both sides of the concave mold insert 18. The diameter of the small hole 19 in the concave mold insert 18 is equal to the outer diameter of the blank tube 2.

[0019] A first force transmission column 22 and a third force transmission column 23 are respectively fixed on the top surfaces of the first vertical spring 20 and the third vertical spring 21. Both the first force transmission column 22 and the third force transmission column 23 penetrate upward through the lower pad 16 and the concave template 17 and extend outside the concave template 17. The distance between the top surface of the first force transmission column 22 and the top surface of the concave template 17 is greater than the distance between the top surface of the third force transmission column 23 and the top surface of the concave template 17. The spring force of the third vertical spring 21 is greater than the spring force of the second vertical spring 11, and the spring force of the second vertical spring 11 is greater than the spring force of the first vertical spring 20.

[0020] A guide hole 24 is provided between the limiting plate 8 and the unloading plate 9, and the fixing rod 13 is slidably engaged with the guide hole 24. The third force transmission column 23 is located directly below the second force transmission column 12.

[0021] A method for drawing and forming a thin tube includes the following steps: S1, the material is fed by the feeding mechanism as follows Figures 1-3 The strip material is pulled from back to front into the area enclosed by the stripper plate 9 and the concave die 17, and the first blank tube 2 of the long strip of thin plate 1 is initially positioned directly below the extending punch 14, as shown. Figure 11 As shown; S2. Control the punch head of the press to move downward. The punch head drives the upper support 5 to move downward. The upper support 5 drives the upper pad 6, the fixed plate 7, the extending punch 14, the second vertical spring 11, and the second force transmission column 12 to move downward synchronously. The second force transmission column 12 drives the limiting plate 8 and the unloading plate 9 to move downward synchronously. The extending punch 14 moves toward the inner hole of the first blank tube 2. At the same time, the unloading plate 9 moves toward the long strip thin plate 1. S3. As the stamping head of the press continues to move downwards, the extending punch 14 is initially inserted into the inner hole of the blank tube 2, as... Figures 12-13 As shown, this is to guide the blank tube 2, and at the same time, the unloading plate 9 presses the long thin plate 1 onto the top surface of the first force transmission column 22. S4. As the punch head of the press continues to move downward, the punch head drives the upper support 5 to continue moving downward. The upper support 5 drives the upper pad 6, the fixed plate 7, the extending punch 14, the second vertical spring 11, and the second force transmission column 12 to move downward synchronously. The second force transmission column 12 drives the limiting plate 8 and the unloading plate 9 to move downward synchronously. Since the spring force of the second vertical spring 11 is greater than the spring force of the first vertical spring 20, the unloading plate 9 presses down on the long strip plate 1 to make it move downward. The long strip plate 1 then drives the blank tube 2 to move towards the small hole 19 of the die insert 18. At the same time, the long strip plate 1 also presses down on the first force transmission column 22 to make it move downward. The first force transmission column 22 compresses the first vertical spring 20 downward. When the long thin plate 1 is blocked by the third force transmission column 23, the lower end of the blank tube 2 is inserted into the small hole 19 of the die insert 18, as follows. Figures 14-15 As shown, this is done to cover the lower end of the blank tube 2. At the same time, since the spring force of the third vertical spring 21 is greater than the spring force of the second vertical spring 11, the unloading plate 9 cannot continue to move downward. Meanwhile, the material is clamped and fixed between the unloading plate 9, the first force transmission column 22 and the third force transmission column 23. S5. As the stamping head of the press continues to move downward, it drives the upper support 5 to continue moving downward. The upper support 5 drives the upper pad 6, the fixed plate 7, and the extending punch 14 to move downward relative to the stationary limiting plate 8 and the unloading plate 9. Meanwhile, the second force transmission column 12 compresses the second vertical spring 11 upward. Simultaneously, the gap H between the fixed plate 7 and the limiting plate 8 gradually decreases. At the same time, the extending punch 14 continues to extend downward into the inner hole of the blank tube 2. When the gap H between the fixed plate 7 and the limiting plate 8 decreases to 1.5mm, the extending punch 14 is exactly in contact with the inner hole of the blank tube 2. Figures 16-17 As shown, at this time, the extending punch 14 is in the extending position; S6. As the punch head of the press continues to move downward, the punch head drives the upper support 5 to continue moving downward. The upper support 5 drives the upper pad 6, the fixed plate 7, and the extending punch 14 to continue moving downward relative to the stationary limiting plate 8 and the unloading plate 9. The extending punch 14 presses down on the bottom closed end of the blank tube 2. The extending punch 14 gradually extends the blank tube 2 downward. At the same time, the gap H between the fixed plate 7 and the limiting plate 8 gradually decreases. When the bottom surface of the fixed plate 7 just presses against the top surface of the limiting plate 8, the extending punch 14 extends the blank tube 2 downward by 1.5mm, thus forming a thin tube with a total length of 8mm. S7. After forming, control the punch head of the press to return to the upward position. The punch head drives the upper support 5 to move upward. The upper support 5 drives the upper pad 6, the fixed plate 7, the extending punch 14, the second vertical spring 11, and the second force transmission column 12 to move upward synchronously. Under the elastic restoring force of the second vertical spring 11, the second force transmission column 12 returns to the position. Then, under the elastic restoring force of the first vertical spring 20, the first force transmission column 22 returns to the position. S8. The worker repeats steps S1 to S7 multiple times to extend each blank tube 2 on the long thin plate 1 downwards, thereby forming the corresponding thin tubes of the required length.

[0022] As can be seen from steps S1 to S7, the worker only needs to initially position the blank tube 2 of the long thin plate 1 directly below the extending punch 14, and then control the punch head of the stamping machine to move downwards. This will sequentially achieve the following: guiding the blank tube 2, covering the lower end of the blank tube 2, allowing the extending punch 14 to enter the extending station, and allowing the extending punch 14 to extend the blank tube 2 downwards by 1.5mm, thereby forming a thin tube of the required length.

[0023] Therefore, compared with the forming method in the workshop, this forming mold does not require workers to put the sleeve on the outside of the blank tube 2, nor does it require workers to manually strike the top of the punch with a wooden hammer to complete the stretching of the blank tube 2. Instead, the blank tube 2 can be automatically stretched by 1.5mm by the downward movement of the upper support 5 of the upper die driven by the punch head of the stamping machine. This not only greatly reduces the labor intensity of the workers, but also realizes the stretching of a blank tube 2 in a short time, and thus realizes the stretching of all the blank tubes 2 on the long thin plate 1 in a short time, thereby greatly improving the forming efficiency of thin tubes.

Claims

1. A forming die for drawing out thin tubular parts, characterized in that: It includes an upper mold and a lower mold. The upper mold includes an upper support (5), an upper pad (6) and a fixing plate (7) sequentially fixed on the bottom surface of the upper support (5). A limiting plate (8) and a stripper plate (9) sequentially fixed together are provided below the fixing plate (7). A gap H (10) is left between the top surface of the limiting plate (8) and the bottom surface of the fixing plate (7). A second vertical spring (11) is fixed inside the upper support (5). A second force transmission column is fixed at the bottom end of the second vertical spring (11). (12) The second force transmission column (12) passes through the upper support (5), upper pad (6), fixed plate (7), and gap H (10) in sequence downwards and is fixed on the limiting plate (8). A fixed rod (13) is fixed on the bottom surface of the upper pad (6) and passes through the fixed plate (7), gap H (10), and limiting plate (8) in sequence downwards and extends into the unloading plate (9). An extension punch (14) that passes through the unloading plate (9) in sequence downwards is fixed on the bottom surface of the fixed rod (13). The lower mold includes a base (15), a lower pad (16), and a concave template (17) that are fixed together from bottom to top. A concave template (17) is fixedly provided with a concave mold insert (18). The top surface of the concave mold insert (18) is flush with the top surface of the concave template (17). A small hole (19) located directly below the extending punch (14) is opened in the concave mold insert (18). A first vertical spring (20) and a third vertical spring (21) located on both sides of the concave mold insert (18) are fixedly provided in the base (15). The first vertical spring (20) and the third vertical spring (21) are respectively fixed with a first force transmission column (22) and a third force transmission column (23). The first force transmission column (22) and the third force transmission column (23) both penetrate upward through the lower pad (16) and the concave template (17) and extend outside the concave template (17). The distance between the top surface of the first force transmission column (22) and the top surface of the concave template (17) is greater than the distance between the top surface of the third force transmission column (23) and the top surface of the concave template (17). The spring force of the third vertical spring (21) is greater than that of the second vertical spring (11), and the spring force of the second vertical spring (11) is greater than that of the first vertical spring (20).

2. A forming die for drawing out thin tubular parts according to claim 1, characterized in that: The upper support (5) of the upper die is fixed to the stamping head of the stamping machine.

3. A forming die for drawing out thin tubular parts according to claim 2, characterized in that: The diameter of the extending punch (14) is equal to the inner diameter of the blank tube (2).

4. A forming die for drawing out thin tubular parts according to claim 3, characterized in that: The extending punch (14) is coaxially arranged with the fixing rod (13).

5. A forming die for drawing out thin tubular parts according to claim 4, characterized in that: A guide hole (24) is provided between the limiting plate (8) and the unloading plate (9), and the fixing rod (13) slides in conjunction with the guide hole (24).

6. A forming die for drawing out thin tubular parts according to claim 5, characterized in that: The diameter of the small hole (19) of the die insert (18) is equal to the outer diameter of the blank tube (2).

7. A forming die for drawing out thin tubular parts according to claim 6, characterized in that: The third force transmission column (23) is located directly below the second force transmission column (12).

8. A method for drawing and forming a thin tubular component, employing a forming die for drawing and forming a thin tubular component as described in claim 7, characterized in that: It includes the following steps: S1. The strip material is pulled from back to front into the area enclosed by the unloading plate (9) and the concave plate (17) by the pulling mechanism, and the first blank tube (2) of the long strip thin plate (1) is initially positioned directly below the extending punch (14). S2. Control the punch head of the press to move downward. The punch head drives the upper support (5) to move downward. The upper support (5) drives the upper pad (6), the fixed plate (7), the extending punch (14), the second vertical spring (11), and the second force transmission column (12) to move downward synchronously. The second force transmission column (12) drives the limiting plate (8) and the unloading plate (9) to move downward synchronously. The extending punch (14) moves toward the inner hole of the first blank tube (2). At the same time, the unloading plate (9) moves toward the long strip thin plate (1). S3. As the punch head of the press continues to move downward, the extension punch (14) is initially inserted into the inner hole of the blank tube (2) to guide the blank tube (2). At the same time, the strip plate (9) presses the long strip plate (1) onto the top surface of the first force transmission column (22). S4. As the punch head of the press continues to move downward, the punch head drives the upper support (5) to continue moving downward. The upper support (5) drives the upper pad (6), the fixed plate (7), the extension punch (14), the second vertical spring (11), and the second force transmission column (12) to move downward synchronously. The second force transmission column (12) drives the limiting plate (8) and the unloading plate (9) to move downward synchronously. Since the spring force of the second vertical spring (11) is greater than the spring force of the first vertical spring (20), the unloading plate (9) presses down on the long strip plate (1) to make it move downward. The long strip plate (1) also drives the blank tube (2) to move towards the small hole (19) of the die insert (18). At the same time, the long strip plate (1) also presses down on the first force transmission column (22) to make it move downward. The first force transmission column (22) compresses the first vertical spring (20) downward. When the long strip plate (1) is blocked by the third force transmission column (23), the lower end of the blank tube (2) is inserted into the small hole (19) of the die insert (18) to cover the lower end of the blank tube (2). At the same time, since the spring force of the third vertical spring (21) is greater than the spring force of the second vertical spring (11), the unloading plate (9) cannot continue to move downward. Meanwhile, the strip is clamped and fixed between the unloading plate (9), the first force transmission column (22) and the third force transmission column (23). S5. As the punch head of the press continues to move downward, the punch head drives the upper support (5) to continue moving downward. The upper support (5) drives the upper pad (6), the fixed plate (7), and the extending punch (14) to move downward relative to the stationary limiting plate (8) and the unloading plate (9). Among them, the second force transmission column (12) compresses the second vertical spring (11) upward. At the same time, the gap H between the fixed plate (7) and the limiting plate (8) gradually decreases. Meanwhile, the extending punch (14) continues to extend downward into the inner hole of the blank tube (2). When the gap H between the fixed plate (7) and the limiting plate (8) decreases to 1.5mm, the extending punch (14) is just fully fitted with the inner hole of the blank tube (2). At this time, the extending punch (14) is in the extending position. S6. As the punch head of the press continues to move downward, the punch head drives the upper support (5) to continue moving downward. The upper support (5) drives the upper pad (6), the fixed plate (7), and the extending punch (14) to continue moving downward relative to the stationary limiting plate (8) and the unloading plate (9). The extending punch (14) presses down on the bottom closed end of the blank tube (2). The extending punch (14) gradually extends the blank tube (2) downward. At the same time, the gap H between the fixed plate (7) and the limiting plate (8) gradually decreases. When the bottom surface of the fixed plate (7) just presses against the top surface of the limiting plate (8), the extending punch (14) just extends the blank tube (2) downward by 1.5mm, thus forming a thin tube with a total length of 8mm. S7. After forming, control the punch head of the press to return to the upper position. The punch head drives the upper support (5) to move upward. The upper support (5) drives the upper pad (6), the fixed plate (7), the extension punch (14), the second vertical spring (11) and the second force transmission column (12) to move upward synchronously. Under the elastic restoring force of the second vertical spring (11), the second force transmission column (12) returns to the position. Then, under the elastic restoring force of the first vertical spring (20), the first force transmission column (22) returns to the position. S8. The worker repeats steps S1 to S7 multiple times to extend each blank tube (2) on the long thin plate (1) downwards, thereby forming the corresponding thin tube of the required length.

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