A die with pre-secured punch

Abstract

The application provides a die cutting die with pre-fixing function and relates to the technical field of die cutting, which comprises a bottom plate, four groups of guide columns are arranged on the upper end face of the bottom plate, and an installation plate is arranged on the upper end face of the guide column; the die cutting die further comprises a die cutting mechanism, the die cutting mechanism comprises a vertical hydraulic cylinder, the upper end face of the installation plate is provided with the vertical hydraulic cylinder, the telescopic end of the vertical hydraulic cylinder is connected with a lifting plate, the lifting plate is in sliding connection with the guide column, the lower end face of the lifting plate is provided with a stamping plate, the lower end face of the stamping plate is connected with a pre-pressing plate, the lower end face of the stamping plate is provided with four groups of pre-pressing springs, the other end of the pre-pressing spring is fixedly connected with the upper end face of the pre-pressing plate, and a forming groove is arranged on the surface of the pre-pressing plate. Through the synergistic effect of the pre-fixing mechanism, the negative pressure control system and the buffer damping adjusting device, the die cutting die with the pre-fixing function realizes stable fixing and positioning control of the workpiece in the whole die cutting process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of punching, more particularly, it relates to a punching die with pre-fixing. BACKGROUND

[0002] In the current punching process, the traditional punching die fixing system of the punching equipment has the technical problems of insufficient fixing timeliness and poor fixing force continuity. These defects affect the precision and stability of the punching process. The fixing device of the traditional punching die can only start the fixing program when the punch is about to contact the workpiece, and the workpiece is temporarily pressed by the basic pressing plate mechanism. This passive and instantaneous fixing method has obvious time lag and uneven fixing force. Due to the time lag of the fixing time, the workpiece is in a free or semi-free state for most of the time during the punching process, and cannot obtain a continuous and stable restraining force, which causes the workpiece to be easily affected by various external interference factors such as vibration, inertial force and cutting reaction force, and to produce a slight displacement.

[0003] During the entire movement process of the workpiece from the initial placement position to the target position directly below the punch in the punching equipment, due to the lack of effective pre-fixing and continuous restraining mechanism, the workpiece is prone to various forms of position deviation and attitude change. This unstable positioning phenomenon has become a key bottleneck problem affecting the punching process quality and production efficiency. During the movement of the workpiece, the acceleration of the start and stop of the conveying mechanism, the gap fit of the guide device, environmental vibration and other factors will interfere with the spatial position of the workpiece. Especially for thin plate, small size or irregular shape workpiece, due to its poor rigidity and unstable gravity center, it is more likely to occur position deviation such as overturning, slipping and skewing during the movement process. When the workpiece finally reaches the position directly below the punch, even if the workpiece is temporarily fixed by the traditional pressing plate, since the workpiece has deviated from the predetermined standard position during the movement process, the starting condition of the punching operation has already been in error, which directly leads to the deviation of the punching hole position, the cutting edge size, the shape profile and other key quality indicators from the design requirements. The cumulative effect of this position deviation is particularly prominent in batch production, and there are obvious size differences and shape inconsistencies between different batches or even the same batch, which affects the interchangeability and assembly precision of the products. The position deviation caused by the position deviation leads to a chain reaction, including abnormal wear of the punch and die, uneven distribution of punching force, shortening of die life and other problems. Not only does it increase the equipment maintenance cost, but also frequently causes production interruption such as shutdown adjustment, rework repair and other problems, which reduces the effective operation time of the equipment and the overall production efficiency, and has a direct negative impact on the economic benefit and market competitiveness of the enterprise. SUMMARY

[0004] (I) Technical problems solved

[0005] In view of the problems in the prior art, the present application provides a die cutting die with pre-fixing to solve the technical problems mentioned in the background art.

[0006] (II) Technical solutions

[0007] To achieve the above object, the present application provides the following technical solutions: A die cutting die with pre-fixing, comprising a bottom plate, four groups of guide columns are arranged on the upper end surface of the bottom plate, and an installation plate is arranged on the upper end surface of the guide column; further comprising a die cutting mechanism, the die cutting mechanism comprises a vertical hydraulic cylinder, the upper end surface of the installation plate is provided with a vertical hydraulic cylinder, the telescopic end of the vertical hydraulic cylinder is connected with a lifting plate, the lifting plate is in sliding connection with the guide column, the lower end surface of the lifting plate is provided with a stamping plate, the lower end surface of the stamping plate is connected with a pre-pressing plate, four groups of pre-pressing springs are arranged on the surface of the pre-pressing plate, the other end of the pre-pressing spring is fixedly connected with the upper end surface of the pre-pressing plate, and a forming groove is formed on the surface of the pre-pressing plate; further comprising a pre-fixing mechanism, the pre-fixing mechanism is provided with two groups, comprising a follow-up pipe, the follow-up pipe is arranged at the bottom of the mold, two groups of communication pipes are arranged on the side wall of the follow-up pipe, the other end of the communication pipe is connected with a negative pressure pipe, and the negative pressure pipe penetrates through the mold.

[0008] Preferably, a horizontal hydraulic cylinder is arranged on the upper end surface of the bottom plate, a mold is connected to the telescopic end of the horizontal hydraulic cylinder, two groups of sliding rails are arranged on the upper end surface of the bottom plate, and the mold is in sliding connection with the sliding rails.

[0009] Preferably, a limiting groove is formed on the surface of the mold, and a discharging groove is further formed on the surface of the limiting groove.

[0010] Preferably, a bottom groove is formed in the inner bottom of the negative pressure pipe, the communication pipe is in through connection with the bottom groove, a center pipe is arranged in the negative pressure pipe, a suction disc is arranged at one end of the center pipe, and a bottom spring is arranged at the other end of the center pipe, and the other end of the bottom spring is fixedly connected with the inner bottom of the bottom groove.

[0011] Preferably, a first fixed disc and a second fixed disc are arranged in the follow-up pipe.

[0012] Preferably, a top pipe is in sliding connection with the follow-up pipe, a sliding sleeve is in sliding connection with the tail end of the top pipe, a top spring is sleeved on the outer surface of the top pipe, one end of the top spring is connected with the side wall of the sliding sleeve, and the other end of the top spring is fixedly connected with the side wall of the top pipe, and two groups of edge plates matched with the top pipe are arranged at one end of the upper end surface of the bottom plate.

[0013] Preferably, a first piston disc, a second piston disc and a third piston disc are arranged on the surface of the top pipe, the first piston disc, the second piston disc and the third piston disc are all arranged in the follow-up pipe, a return spring is arranged between the second piston disc and the third piston disc, one end of the return spring is connected with the side wall of the second piston disc, and the other end of the return spring is connected with the side wall of the second fixed disc.

[0014] Preferably, the first piston disc, the second piston disc and the third piston disc are provided with side edge strips on one side, and two groups of negative pressure holes and two groups of back pressure holes are formed on the surfaces of the side edge strips, and a plurality of side edge holes are formed on the side walls of the top pipe.

[0015] Preferably, the first piston disc, the second piston disc and the third piston disc are provided with return pipes connected through the other side, the side wall of the third piston disc is provided with a follow-up rod, the follow-up rod is slidably connected with the side wall of a follow-up pipe, the side wall of the follow-up pipe is threadedly connected with a threaded rod, the side wall of the threaded rod is connected with a damping rod, and the damping rod is matched with the return pipe.

[0016] Preferably, a first oil cavity is formed between the first piston disc and the side wall of one end of the follow-up pipe, a second oil cavity is formed between the third piston disc and the side wall of the other end of the follow-up pipe, a first negative pressure cavity is formed between the first fixed disc and the second piston disc, and a second negative pressure cavity is formed between the second fixed disc and the third piston disc.

[0017] (Three) beneficial effects

[0018] Compared with the prior art, the present application provides a punching die with a pre-fixing function, which has the following beneficial effects: the punching die with the pre-fixing function realizes the stable fixing and positioning control of the workpiece in the whole punching process through the synergistic effect of the pre-fixing mechanism, the negative pressure control system and the buffer damping adjusting device.

[0019] The core of the punching die is to establish a continuous pre-fixing mechanism for the whole workpiece processing process, which changes the problem that the traditional punching equipment can only perform simple pressing plate fixing at the last moment. Through the negative pressure adsorption system, the workpiece can obtain a continuous and stable fixing force during the whole process from placing to punching completion, and the processing precision is improved. When the mold advances and triggers the pre-fixing mechanism, the complex piston system in the follow-up pipe starts to work in coordination, and through the displacement control of the first piston disc, the second piston disc and the third piston disc, the sealing establishment of the negative pressure chamber and the accurate adjustment of the vacuum degree are realized. The hierarchical control design of the multi-stage piston makes the generation and maintenance of negative pressure more stable and reliable, avoiding the pressure fluctuation and leakage problems easily occurring in single chamber systems.

[0020] The punching die realizes parameter optimization under different workpiece materials and processing requirements through a damping adjustment mechanism, and improves the versatility and production adaptability of the equipment. The cooperation design of the damping rod and the return pipe uses the flow resistance of hydraulic oil to control the reset speed of the piston system. When the end of the return pipe contacts the damping rod, the flow speed of the hydraulic oil is controlled, thereby prolonging the rebound time and negative pressure maintenance time of the return spring. This time control mechanism based on fluid damping is more stable and reliable than traditional mechanical or electronic delay systems, and is not easily affected by external factors such as environmental temperature and electromagnetic interference, thereby ensuring the consistency and repeatability of the fixed time. Through the rotation adjustment of the threaded rod, the operator can conveniently replace the damping rod of different specifications to realize the adjustment of the damping coefficient and the setting of the fixed time.

[0021] The hydraulic balance system of the double-oil-cavity realizes stable control of the piston movement through pressure balance and flow regulation between the first oil cavity and the second oil cavity. In the process of fixed force application, the buffering effect of the hydraulic oil avoids damage to the workpiece and the die caused by mechanical impact; in the process of fixed force release, the damping control of the hydraulic oil ensures the smooth transition of the workpiece release, preventing the workpiece from bouncing or moving due to sudden release. This hydraulic buffering mechanism not only protects the surface quality of the workpiece, but also prolongs the service life of the die and the equipment.

[0022] The buffering mechanism design of the pre-pressing plate and the pre-pressing spring further optimizes the punching force application process. When the pre-pressing plate abuts against the upper end surface of the die, the buffering effect of the pre-pressing spring makes the transmission of the punching force more stable and gradual, avoiding the adverse effects of sudden impact on the stress distribution inside the workpiece, reducing the incidence of processing defects such as cracks and tears, and ensuring the accuracy and stability of the die movement, reducing the vibration and noise of the equipment operation, and improving the working environment conditions.

[0023] In summary, this punching die with pre-fixing function successfully solves the problems of unreliable workpiece fixation and unstable processing precision of traditional punching equipment, and provides an effective solution for the technical upgrading and quality improvement of the punching processing industry. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is the overall structure schematic diagram of a punching die with pre-fixing function in the application;

[0025] Figure 2 It is the structure schematic diagram of the vertical hydraulic cylinder and the punching plate in the application;

[0026] Figure 3 It is the structure schematic diagram of the punching plate and the pre-pressing plate in the application;

[0027] Figure 4 It is the structure schematic diagram of the horizontal hydraulic cylinder and the bottom plate in the application;

[0028] Figure 5 is a schematic view of the structure of the follower pipe and the top pipe in the present application;

[0029] Figure 6 is a schematic view of the structure of the negative pressure pipe and the center pipe in the present application;

[0030] Figure 7 is a schematic view of the structure of the follower pipe and the top pipe in the present application;

[0031] Figure 8 is a schematic view of the structure of the follower pipe and the top pipe in the present application;

[0032] Figure 9 is a schematic view of the structure of the follower pipe and the top pipe in the present application;

[0033] Figure 10 is a schematic view of the structure of the follower pipe and the top pipe in the present application;

[0034] Figure 11 is a schematic view of the structure of the follower pipe and the top pipe in the present application.

[0035] In the figure: 11, bottom plate; 12, guide column; 13, mounting plate; 21, vertical hydraulic cylinder; 22, lifting plate; 23, punching plate; 24, pre-pressing plate; 25, pre-pressing spring; 26, forming groove; 27, transverse hydraulic cylinder; 28, die; 29, slide rail; 31, follower pipe; 32, communication pipe; 33, negative pressure pipe; 34, bottom groove; 35, center pipe; 36, suction cup; 37, bottom spring; 38, first fixed disc; 39, second fixed disc; 210, limiting groove; 211, discharge groove; 310, top pipe; 311, sliding sleeve; 312, top spring; 313, edge plate; 314, first piston disc; 315, second piston disc; 316, return spring; 317, side strip; 318, negative pressure hole; 319, back pressure hole; 320, side hole; 321, return pipe; 322, follower rod; 323, threaded rod; 324, damping rod; 325, first oil cavity; 326, second oil cavity; 327, first negative pressure cavity; 328, second negative pressure cavity; 329, third piston disc. DETAILED DESCRIPTION

[0036] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that, unless otherwise specified, all the technical and scientific terms used in the present application have the same meaning as that generally understood by the ordinary skilled person in the technical field to which the present application belongs.

[0038] In the present application, the orientation such as "upper, lower" is generally directed to the direction shown in the drawings or the vertical, perpendicular or gravity direction unless otherwise stated; similarly, for the convenience of understanding and description, "left, right" is generally directed to the left and right shown in the drawings; "inner, outer" refers to the inner and outer relative to the contour of each component, but the above orientation words are not used to limit the present application.

[0039] Please refer to Figures 1 to 11 A kind of with pre-fixed die cutting die, including bottom plate 11, bottom plate 11 upper end surface is equipped with four sets of guide column 12, guide column 12 upper end surface is equipped with mounting plate 13;It also includes punching mechanism, punching mechanism includes vertical hydraulic cylinder 21, mounting plate 13 upper end surface is equipped with vertical hydraulic cylinder 21, vertical hydraulic cylinder 21 telescopic end is connected with lifting plate 22, lifting plate 22 is slidably connected with guide column 12, lifting plate 22 lower end surface is equipped with punch plate 23, punch plate 23 lower end surface is connected with pre-pressing plate 24, punch plate 23 lower end surface is equipped with four sets of pre-pressing spring 25, pre-pressing spring 25 other end is fixedly connected with pre-pressing plate 24 upper end surface, pre-pressing plate 24 surface is provided with forming groove 26, bottom plate 11 upper end surface is equipped with transverse hydraulic cylinder 27, transverse hydraulic cylinder 27 telescopic end is connected with mould 28, bottom plate 11 upper end surface is equipped with two sets of slide rail 29, mould 28 is slidably connected with slide rail 29, the surface of mould 28 is provided with limit groove 210, limit groove 210 surface is provided with discharge slot 211 again.

[0040] The pre-fixing mechanism is provided with two groups, including a follower pipe 31 provided at the bottom of the mold 28, two groups of communication pipes 32 provided on the side wall of the follower pipe 31, a negative pressure pipe 33 connected to the other end of the communication pipe 32, the negative pressure pipe 33 penetrating through the mold 28, a bottom groove 34 provided at the inner bottom of the negative pressure pipe 33, the communication pipe 32 being connected to the bottom groove 34 in penetration, a center pipe 35 provided in the negative pressure pipe 33, a suction cup 36 provided at one end of the center pipe 35, a bottom spring 37 provided at the other end of the center pipe 35 and fixedly connected to the inner bottom of the bottom groove 34, a first fixing disc 38 and a second fixing disc 39 provided in the follower pipe 31, a top pipe 310 slidingly connected in the follower pipe 31, a sliding sleeve 311 slidingly connected to the end of the top pipe 310, a top spring 312 sleeved on the outer surface of the top pipe 310, one end of the top spring 312 being connected to the side wall of the sliding sleeve 311 and the other end being fixedly connected to the side wall of the top pipe 310, two groups of edge plates 313 adapted to the top pipe 310 being provided at one end of the upper end surface of the bottom plate 11, a first piston disc 314, a second piston disc 315 and a third piston disc 329 being provided on the surface of the top pipe 310, the first piston disc 314, the second piston disc 315 and the third piston disc 329 being located in the follower pipe 31, a return spring 316 being provided between the second piston disc 315 and the third piston disc 329, one end of the return spring 316 being connected to the side wall of the second piston disc 315 and the other end being connected to the side wall of the second fixing disc 39, a side edge strip 317 being provided at one side of the first piston disc 314, the second piston disc 315 and the third piston disc 329, two groups of negative pressure holes 318 and two groups of back pressure holes 319 being provided on the surface of the side edge strip 317, a plurality of side edge holes 320 being provided on the side wall of the top pipe 310, a return flow pipe 321 being connected in penetration at the other side of the first piston disc 314, the second piston disc 315 and the third piston disc 329, a follower rod 322 being provided on the side wall of the third piston disc 329 and slidingly connected to the side wall of the follower pipe 31, a threaded rod 323 being threadedly connected to the side wall of the follower pipe 31, a damping rod 324 being connected to the side wall of the threaded rod 323 and adapted to the return flow pipe 321, a first oil cavity 325 being formed between the first piston disc 314 and the side wall of one end of the follower pipe 31, a second oil cavity 326 being formed between the third piston disc 329 and the side wall of the other end of the follower pipe 31, a first negative pressure cavity 327 being formed between the first fixing disc 38 and the second piston disc 315, and a second negative pressure cavity 328 being formed between the second fixing disc 39 and the third piston disc 329.

[0041] When punching, the vertical hydraulic cylinder 21 is started, the telescopic end of the vertical hydraulic cylinder 21 pushes the lifting plate 22 to move downward, the lifting plate 22 moves downward to drive the punching plate 23 and the pre-pressing plate 24 to move downward synchronously, when the pre-pressing plate 24 abuts against the upper end surface of the die 28, the vertical hydraulic cylinder 21 continuously pushes the lifting plate 22 to move downward together with the punching plate 23, at this time, the pre-pressing spring 25 is compressed, the punching plate 23 continues to press downward to punch the workpiece fixedly arranged in the limiting groove 210 through the forming groove 26, after the punching is completed, the telescopic end of the vertical hydraulic cylinder 21 is retracted to drive the punching mechanism to move upward as a whole, the punched workpiece falls through the discharge groove 211 to the upper end surface of the bottom plate 11;

[0042] After the punching is finished, the waste in the limiting groove 210 needs to be taken out, and then the new workpiece is placed. After that, the transverse hydraulic cylinder 27 is started, and the telescopic end of the transverse hydraulic cylinder 27 pushes the mold 28 to push out along the sliding rail 29 until the sliding sleeve 311 abuts against the side wall of the edge plate 313, and the transverse hydraulic cylinder 27 stops pushing. At this time, the waste in the limiting groove 210 is taken out, and the new workpiece is placed. Then the transverse hydraulic cylinder 27 continues to push forward, and the top spring 312 is compressed at this time. With the follow-up pipe 31 continuing to move forward, the top pipe 310 starts to slide into the follow-up pipe 31, and the first piston disc 314, the second piston disc 315 and the third piston disc 329 are synchronously moved into the follow-up pipe 31. At this time, the back pressure hole 319 is disconnected with the communication pipe 32, and the first negative pressure cavity 327 and the second negative pressure cavity 328 form a vacuum state, generating negative pressure. Until the negative pressure hole 318 is communicated with the communication pipe 32, the negative pressure in the first negative pressure cavity 327 and the second negative pressure cavity 328 is transmitted to the negative pressure pipe 33 through the communication pipe 32. The generation of negative pressure makes the suction cup 36 tightly suck the upper workpiece through the central pipe 35, and at the same time, the central pipe 35 is lowered under the action of negative pressure to overcome the elastic force of the bottom spring 37, and then abuts against the upper end surface of the negative pressure pipe 33 to realize the downward pulling force on the upper workpiece. When the top pipe 310 slides inwards, the return spring 316 is compressed, and the air in the cavity between the second piston disc 315 and the second fixed disc 39 is discharged along the top pipe 310 through the side hole 320 on the top pipe 310. At the same time, the air in the cavity between the first piston disc 314 and the first fixed disc 38 is also discharged along the top pipe 310 through the side hole 320 on the top pipe 310. When the top pipe 310 slides into the follow-up pipe 31, the hydraulic oil in the second oil cavity 326 flows into the first oil cavity 325 through the backflow pipe 321. When the end of the backflow pipe 321 contacts the damping rod 324, the flow speed of the hydraulic oil is slowed down. After the suction cup 36 sucks the upper workpiece, the transverse hydraulic cylinder 27 starts to return, and the sliding sleeve 311 is disconnected with the edge plate 313. After the pushing force disappears, the return spring 316 starts to slowly rebound. The setting of the damping rod 324 can make the hydraulic oil in the first oil cavity 325 flow slowly into the second oil cavity 326, prolong the rebound time of the return spring 316, and then ensure that the suction cup 36 is tightly fixed on the new workpiece before the new workpiece is punched. When the back pressure hole 319 is communicated with the communication pipe 32, the negative pressure disappears, and at this time the suction force of the suction cup 36 on the new workpiece is released, and then the fixation of the workpiece and the limiting groove 210 is released. In this process, the cavity between the first piston disc 314 and the first fixed disc 38 and the cavity between the second piston disc 315 and the second fixed disc 39 are enlarged, and air is sucked from the outside through the side hole 320 on the top pipe 310. The hydraulic oil in the first oil cavity 325 also gradually flows back to the second oil cavity 326 through the backflow pipe 321. At this time, the pre-fixing and releasing of the punched workpiece are completed.The damping rod 324 is screwed with the screw rod 323 and the follow-up pipe 31, when the resistance needs to be changed, the screw rod 323 is rotated to dismount the damping rod 324, and then the appropriate damping rod 324 is replaced.

[0043] In all the above-mentioned solutions, the connection between the two components can be selected according to the actual situation, such as welding, bolt and nut connection, bolt or screw connection, or other known connection methods, which will not be described one by one here. In the above, whenever it is mentioned that it is fixedly connected, it is preferred to be welded. Although the embodiments of the application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A pre-fixed punching die, comprising a base plate (11), the upper surface of which is provided with four sets of guide posts (12), and the upper surface of the guide posts (12) is provided with a mounting plate (13); further comprising a punching mechanism, the punching mechanism comprising a vertical hydraulic cylinder (21), the upper surface of which is provided with the vertical hydraulic cylinder (21), the telescopic end of which is connected to a lifting plate (22), the lifting plate (22) being slidably connected to the guide posts (12), the lower surface of which is provided with a stamping plate (23), and the lower surface of which is connected to a... The pre-press plate (24) has four sets of pre-press springs (25) on the lower end face of the stamping plate (23). The other end of the pre-press springs (25) is fixedly connected to the upper end face of the pre-press plate (24). A forming groove (26) is opened on the surface of the pre-press plate (24). The pre-press plate (24) also includes a pre-fixing mechanism, which has two sets, including a follower tube (31). The follower tube (31) is located at the bottom of the mold (28). The side wall of the follower tube (31) is provided with two sets of connecting tubes (32). The other end of the connecting tube (32) is connected to a negative pressure tube (33). The negative pressure tube (33) penetrates the mold (28). Its characteristics are: The negative pressure tube (33) has a bottom groove (34) at the bottom. The connecting tube (32) is connected to the bottom groove (34). The negative pressure tube (33) has a central tube (35). One end of the central tube (35) has a suction cup (36) and the other end has a bottom spring (37). The other end of the bottom spring (37) is fixedly connected to the bottom of the bottom groove (34). The follower tube (31) has a first fixed plate (38) and a second fixed plate (39). The follower tube (31) has a top tube (310) slidably connected. The end of the top tube (310) is slidably connected to a sliding sleeve (311). The outer surface of the top tube (310) is fitted with a top spring (312). One end of the top spring (312) is connected to the side wall of the sliding sleeve (311), and the other end is fixedly connected to the side wall of the top tube (310). The upper end of the base plate (11) is provided with two sets of edge plates (313) adapted to the top tube (310). The surface of the top tube (310) is provided with a first piston disc (314), a second piston disc (315), and a third piston disc (329). The first piston disc (314), the second piston disc (315), and the third piston disc (329) are all located inside the follower tube (31). A return spring (316) is provided between the second piston disc (315) and the third piston disc (329). One end of the return spring (316) is connected to the side wall of the second piston disc (314). 5) The side wall is connected, and the other end is connected to the side wall of the second fixed plate (39). The first piston plate (314), the second piston plate (315) and the third piston plate (329) are provided with side strips (317) on one side. The side strips (317) have two sets of negative pressure holes (318) and two sets of back pressure holes (319) on their surface. The top tube (310) has multiple sets of side holes (320) on its side wall. The first piston plate (314), the second piston plate (315) and the third piston plate (329) are connected to a return pipe (321) on the other side. The third piston plate (329) is provided with a follower rod (322) on its side wall. The follower rod (322) is connected to the side wall of the follower tube (31). The sliding connection is provided. A threaded rod (323) is threadedly connected to the side wall of the follower tube (31). A damping rod (324) is connected to the side wall of the threaded rod (323). The damping rod (324) is adapted to the return tube (321). A first oil chamber (325) is formed between the first piston disc (314) and one end side wall of the follower tube (31). A second oil chamber (326) is formed between the third piston disc (329) and the other end side wall of the follower tube (31). A first negative pressure chamber (327) is formed between the first fixed disc (38) and the second piston disc (315). A second negative pressure chamber (328) is formed between the second fixed disc (39) and the third piston disc (329).

2. A pre-fixed punching die according to claim 1, characterized in that: The upper surface of the base plate (11) is provided with a transverse hydraulic cylinder (27), the telescopic end of the transverse hydraulic cylinder (27) is connected to a mold (28), the upper surface of the base plate (11) is provided with two sets of slide rails (29), and the mold (28) is slidably connected to the slide rails (29).

3. A pre-fixed punching die according to claim 2, characterized in that: The mold (28) has a limiting groove (210) on its surface, and the limiting groove (210) has a discharge groove (211) on its surface.

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