Copper alloy thick plate leading-out end forming device and method based on cold extrusion process

Abstract

The invention belongs to the technical field of copper alloy leading-out end forming, and particularly relates to a copper alloy thick plate leading-out end forming device and method based on a cold extrusion process, and the copper alloy thick plate leading-out end forming device comprises a rack, supporting feet, a main hydraulic cylinder and a die holder. Through the synergistic effect of the main hydraulic cylinder and the auxiliary hydraulic cylinder, bi-directional active pressing on the blank is achieved, and the forming quality of the thick plate leading-out end is remarkably improved. A traditional cold extrusion process only depends on single vertical pressure to drive metal to flow, and when a thick plate blank is formed, the far end of a leading-out end far away from a pressure applying point is prone to generating the defect of vacancy due to long flowing path and large resistance. When the main hydraulic cylinder exerts vertical pressure, the auxiliary hydraulic cylinder drives the side pushing frame and the long handle arm to exert active pushing force consistent with the flowing direction of metal on the edge of the side end of a blank, the two-way extrusion effect is formed, and the metal is forced to sequentially and densely fill all corners of a forming hole of the leading-out end. The structural design solves the problem of insufficient far-end filling from the source.

Description

Technical Field

[0001] This invention relates to the field of copper alloy lead-out end forming technology, specifically to a copper alloy thick plate lead-out end forming device and method based on cold extrusion process. Background Technology

[0002] Cold extrusion is a plastic forming technique that applies pressure to a metal billet using a die at room temperature, causing it to undergo plastic deformation to obtain the desired shape, size, and mechanical properties. This process features high material utilization, high production efficiency, good surface quality of the parts, and continuous metal flow lines, making it particularly suitable for forming non-ferrous metals with good plasticity, such as copper and its alloys. Copper alloy thick plate leads, as an important electrical connection structural element, are widely used in power electronics, new energy vehicles, and rail transportation. They typically consist of a copper alloy substrate of a certain thickness and connection terminals extending laterally from the substrate, requiring good conductivity, mechanical strength, and connection reliability.

[0003] Existing technologies have the following shortcomings: Currently, traditional processes for forming the lead-out ends of thick copper alloy plates mainly employ welding or machining. Welding connects pre-fabricated lead-out ends to the thick plate substrate via brazing or fusion welding. However, the welded area is prone to changes in the microstructure of the heat-affected zone, leading to a decrease in conductivity and mechanical properties at the joint, and also presenting quality risks such as incomplete welds and weld detachment. Machining directly removes excess material from the thick plate blank through cutting to form the lead-out end. This method results in significant material waste, low processing efficiency, and the cutting process interrupts metal flow lines, affecting the product's conductivity and fatigue strength. Although a few solutions attempt to use cold extrusion for one-piece forming, conventional cold extrusion equipment often relies solely on pressure in a single vertical direction to force metal flow when dealing with thick copper alloy plates (e.g., 5mm or more). Due to the high flow resistance and long flow path of thick plate materials, the far end of the lead-out end (i.e., the deepest part of the cavity) is easily not fully filled, making it difficult to guarantee forming quality. In addition, existing devices lack an effective active force compensation mechanism during lateral forming, making it impossible to actively intervene and control the direction of metal flow, which restricts the stability of the forming process and the dimensional accuracy of the product. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a copper alloy thick plate lead-out end forming device and method based on cold extrusion process, which solves the current problem that filling cannot guarantee reaching the very end of the cavity.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a copper alloy thick plate lead-out end forming device based on cold extrusion process, comprising a frame and a main hydraulic cylinder and a die holder mounted on the frame, wherein the die holder has a forming cavity for accommodating the blank, and further comprising: A side pusher is movably mounted on the side end of the frame, and the end of the side pusher is provided with a long handle arm for abutting or engaging with the edge of the blank side end; The auxiliary hydraulic cylinder is installed on the side of the frame. Its piston rod is connected to the side pusher frame for driving the side pusher frame to move towards the billet. While the main hydraulic cylinder drives the upper die to apply the main extrusion force to the billet, the auxiliary hydraulic cylinder drives the side pusher to apply the lateral thrust to the billet through the long handle arm, so as to force the metal of the billet to fill towards the forming hole at the lead-out end.

[0006] In some embodiments, the end of the long handle is provided with a notch adapted to the profile of the side edge of the billet, the notch engaging with the billet when the side pusher moves.

[0007] In some embodiments, the sidewall of the frame is provided with transverse grooves through which the side pusher passes, the transverse grooves guiding and limiting the movement of the side pusher.

[0008] In some embodiments, an extension plate is provided on the frame, and a lateral stabilizing mechanism is connected between the extension plate and the side push frame. The lateral stabilizing mechanism includes a spring rod and a damping sleeve. One end of the spring rod is connected to the side push frame, and the other end is movably inserted into the damping sleeve. A spring is sleeved on the outside of the spring rod.

[0009] In some embodiments, the damping sleeve is fixedly embedded inside the extension plate, and the spring rod compresses the spring and inserts into the damping sleeve when the side pusher moves, in order to absorb the lateral movement impact and realize the smooth reset of the side pusher.

[0010] Another problem that this invention aims to solve is to provide a method for forming the lead-out end of a thick copper alloy plate based on a cold extrusion process, comprising the following steps: Step 1: Place the pre-treated blank into the lower mold cavity of the mold base, and maintain the initial gap between the long handle arm at the end of the side pusher and the side edge of the blank. Step 2: Start the main hydraulic cylinder to drive the upper mold downward, close the cavity and apply the first preset pressure to the blank, so that the blank fits the bottom surface of the mold cavity, while the auxiliary hydraulic cylinder remains locked. Step 3: The main hydraulic cylinder continues to pressurize to the second preset pressure. At the same time, the auxiliary hydraulic cylinder is activated to drive the side pusher to move towards the billet, so that the long handle arm grabs the side edge of the billet and applies the third preset pressure. The application time of the second preset pressure and the third preset pressure overlaps, forming a bidirectional extrusion effect. Step 4: When the pressure inside the cavity reaches the fourth preset pressure, the main hydraulic cylinder and the auxiliary hydraulic cylinder simultaneously enter the pressure holding state and maintain the pressure for T seconds. Step 5: First, the auxiliary hydraulic cylinder depressurizes and returns to its original position. After a delay of Δt, the main hydraulic cylinder depressurizes and opens the mold. Finally, the ejection mechanism ejects the molded finished product.

[0011] In some embodiments, in step one, the initial gap is 0.5-2mm, which is used to ensure that the side pusher can quickly contact the blank when it moves, while avoiding positional displacement before mold closing.

[0012] In some embodiments, in step two, the first preset pressure is 30%-50% of the yield strength of the billet material, used to achieve initial bonding and venting of the billet.

[0013] In some embodiments, in step three, the direction of the third preset pressure is consistent with the direction of metal flow toward the lead-out end forming hole, and the overlap time between the second preset pressure and the third preset pressure at least covers the process of metal filling the far end of the lead-out end forming hole.

[0014] In some embodiments, in step four, the fourth preset pressure is set to 1.1-1.3 times the second preset pressure, and the pressure holding time T is 3-8 seconds; in step five, the delay time Δt is 0.5-2 seconds, used to ensure that the lateral force is completely released before mold opening.

[0015] Compared with the prior art, the present invention provides a copper alloy thick plate lead-out end forming device and method based on cold extrusion process, which has the following beneficial effects: This invention relates to a copper alloy thick plate lead-out end forming device and method based on cold extrusion technology. Through the coordinated action of a main hydraulic cylinder and an auxiliary hydraulic cylinder, it achieves bidirectional active pressure on the billet, significantly improving the forming quality of the thick plate lead-out end. Traditional cold extrusion processes rely solely on a single vertical pressure to drive metal flow. When forming thick plate billets, the lead-out end, far from the pressure point, is prone to defects due to its long flow path and high resistance. This invention, while applying vertical pressure with the main hydraulic cylinder, simultaneously applies an active thrust to the side edge of the billet in the same direction as the metal flow through the auxiliary hydraulic cylinder-driven side pusher and long-handled arm. This creates a bidirectional extrusion effect, forcing the metal to fill every corner of the lead-out end forming hole in an orderly and dense manner. This structural design solves the problem of insufficient filling at the far end from the source, ensuring the shape integrity and dimensional accuracy of the lead-out end. Simultaneously, the one-piece forming process avoids the microstructure changes in the heat-affected zone caused by welding, ensuring the continuity and integrity of the metal flow lines, resulting in a product with both excellent electrical conductivity and mechanical strength. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram showing the placement of the copper alloy plate on the side and inside of the present invention. Figure 3 This is a schematic diagram showing the location of the constant groove and the spring rod in this invention. Figure 4 This is a schematic diagram of the overall connection structure of the long handle arm and side pusher frame of the present invention.

[0017] In the diagram: 1. Frame; 2. Support leg; 3. Copper alloy plate; 4. Main hydraulic cylinder; 5. Mold base; 6. Side push frame; 7. Extension plate; 8. Auxiliary hydraulic cylinder; 9. Horizontal groove; 10. Spring rod; 11. Damping sleeve; 12. Long handle arm. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Please see Figure 1-4In this implementation scheme: the copper alloy thick plate lead-out end forming device based on cold extrusion process includes a frame 1 and support legs 2 for load-bearing, a main hydraulic cylinder 4 for realizing cold extrusion forming, and a mold base 5 as the forming space. The mold base 5 is composed of upper and lower cavities, with the middle combined cavity serving as the forming space. When the main hydraulic cylinder 4 extrudes the blank, the upper cavity of the mold base 5 usually contacts the blank first, sealing it in the cavity, and then applies high pressure, forcing the metal to flow to the side lead-out end hole. A side pusher 6 is set at the side end of the frame 1 to realize active lateral supplementary pressure, so that the movement of the side pusher 6 can drive the blank to move, so that when the blank is pressed, it not only actively tends to the position with less resistance, but also has the effect of active lateral pressure, avoiding the situation where the far end of the mold is not fully filled when pressing thicker blanks.

[0022] A copper alloy plate 3 (blank) is placed inside the frame 1.

[0023] To enable the side pusher 6 to drive the copper alloy plate 3 and achieve lateral movement, a long handle arm 12 for inverting the copper alloy plate 3 is provided at the side end of the side pusher 6. The end of the long handle arm 12 is provided with a notch (e.g., Figure 4 As shown in the figure, the copper alloy plate 3 can be moved synchronously by pressing against the side edge of the copper alloy plate 3 through the notch.

[0024] To ensure the stability of the side pusher 6, a slider perpendicular to the side pusher 6 is provided at the end of the side pusher 6, and the slider is embedded inside the frame 1. The stable movement of the side pusher 6 is achieved by the sliding of the slider inside the frame 1.

[0025] A transverse groove 9 is opened on the side wall of the frame 1 where the side pusher 6 is connected. The transverse groove 9 is used to allow the side pusher 6 to pass laterally through the side wall of the frame 1 and to reserve space for the lateral movement of the side pusher 6.

[0026] An auxiliary hydraulic cylinder 8 is provided at the side end of the frame 1 to provide lateral driving force for the side pusher 6. The auxiliary hydraulic cylinder 8 is connected to the side pusher 6 through the piston rod and realizes transmission.

[0027] To further improve the moving stability of the side pusher 6, an extension plate 7 is provided at the side end of the frame 1, and a spring rod 10 and a damping sleeve 11 for stable connection of the components are provided between the extension plate 7 and the side pusher 6. The damping sleeve 11 is embedded in the interior of the extension plate 7 as a connecting member between the side pusher 6 and the extension plate 7. A spring is sleeved on the outside of the spring rod 10, which, together with the damping sleeve 11, forms a lateral stabilizing element. Its specific working steps are as follows: When the auxiliary hydraulic cylinder 8 pushes the side pusher 6 to move, the side pusher 6 moves toward the spring rod 10 and compresses the spring so that the spring rod 10 is embedded in the damping sleeve 11. When the side pusher 6 returns to its original position, the outer spring of the spring rod 10 returns to its original position and expands. This can prevent the side pusher 6 from colliding with the frame 1.

[0028] Based on the above-described apparatus, the present invention also provides a cold extrusion forming method for the lead-out end of a thick copper alloy plate. This method, implemented using the aforementioned apparatus, includes the following steps: Step 1: Billet Pretreatment and Loading First, the copper alloy thick plate billet 3 is cleaned to remove rolling oxide scale and oil stains, and a special cold extrusion lubricant (such as molybdenum disulfide grease) is uniformly coated on its surface to reduce frictional resistance during the extrusion process and improve die life and product surface quality.

[0029] Then, the processed blank 3 is placed in the lower mold cavity of the mold base 5 inside the frame 1, and is initially positioned by the side wall of the mold base 5 and the positioning pin (not shown in the figure) set at the bottom of the cavity. At this time, the side pusher 6 is in the initial retracted position, and the notch at the end of the long handle arm 12 at its end is opposite to the side edge of the blank 3, and there is a small initial gap between them (preferably 0.5-2mm). The gap is set to ensure that the side pusher 6 can quickly contact the blank 3 and apply force when it moves later, while avoiding accidental contact with the blank 3 before mold closing, which would cause positional displacement.

[0030] Step 2: One-time mold closing and establishment of closed cavity The main hydraulic cylinder 4 is activated, driving the upper mold assembly of the mold base 5 to descend rapidly. When the upper mold assembly approaches the blank 3, the hydraulic system switches to a slow-speed feed mode to precisely control the mold closing process.

[0031] The upper mold assembly first closes with the lower mold assembly to form a closed molding cavity that only connects to the forming hole at the lead end, completely enclosing the blank 3 inside the mold cavity.

[0032] The upper die assembly continues to descend until it contacts the upper surface of the blank 3, and applies a first preset pressure P1. The first preset pressure P1 is 30%-50% of the material's yield strength. Under this pressure, the blank 3 undergoes a small amount of initial plastic deformation, causing its lower surface to completely adhere to the bottom surface of the lower die cavity, and its upper surface to make close contact with the upper die working surface. This expels most of the air from the cavity and forces a small amount of metal from the blank 3 to begin pre-flowing towards the inlet of the forming hole at the lead-out end, creating favorable conditions for subsequent main extrusion.

[0033] During this process, the side pusher 6 remains stationary, the auxiliary hydraulic cylinder 8 is in standby mode, and its oil circuit is locked to ensure that the side pusher 6 will not be displaced due to the vibration of the main extrusion.

[0034] Step 3: Synchronous linkage of main extrusion and lateral reinforcement (core step) Maintaining the closed state of the upper mold assembly over the cavity, the main hydraulic cylinder 4 continues to apply pressure, applying a second preset pressure P2 to the billet 3. The second preset pressure P2 is greater than the first preset pressure P1, preferably 1.5-2 times the material's yield strength. Under this pressure, the main metal of the billet 3 begins to undergo significant plastic flow in the direction of least resistance—that is, the direction of the forming hole at the lead-out end.

[0035] At the same time, the control system (not shown in the figure) issues a command according to a preset program to start the auxiliary hydraulic cylinder 8. The piston rod of the auxiliary hydraulic cylinder 8 extends, pushing the side pusher 6 to move horizontally along the transverse groove 9 toward the billet 3.

[0036] The long handle 12 at the end of the side pusher 6 first eliminates the initial gap reserved in step 1, and then engages the side edge of the blank 3 through the notch at its end. As the auxiliary hydraulic cylinder 8 continues to pressurize, the side pusher 6 applies a third preset pressure P3 to the side edge of the blank 3 through the long handle 12. It should be noted that the direction of the third preset pressure P3 is exactly the same as the direction of metal flow towards the forming hole at the lead end, that is, the thrust direction of the auxiliary hydraulic cylinder 8 is consistent with the lateral component direction of the metal flow driven by the main hydraulic cylinder 4.

[0037] The application of the second preset pressure P2 and the application of the third preset pressure P3 overlap in time, thereby forming a bidirectional extrusion effect inside the billet 3: The main hydraulic cylinder 4 applies pressure from above downwards, forcing the metal to flow downwards and laterally, filling the cavity body; The auxiliary hydraulic cylinder 8 pushes the billet 3 from the side to move it toward the forming hole at the lead-out end, which is equivalent to actively applying a thrust from the source of metal flow, forcing more and denser metal to flow into the forming hole at the lead-out end.

[0038] This bidirectional extrusion effect ensures that the far end of the forming hole (i.e. the most difficult part to fill) is completely filled, fundamentally avoiding defects caused by excessively long metal flow paths or excessive flow resistance.

[0039] Step 4: Lateral stabilization and pressure holding / compensation During the entire process of the auxiliary hydraulic cylinder 8 pushing the side pusher 6 to move, the side pusher 6 simultaneously drives the spring rod 10 connected to it to move into the damping sleeve 11, compressing the spring outside the spring rod 10. During this process: The compression process of the spring absorbs the impact energy and minute vibrations that may be generated by lateral movement; The damping medium (such as hydraulic oil or friction material) inside the damping sleeve 11 provides stable motion resistance, ensuring that the side pusher 6 moves at a uniform and smooth speed, preventing impact damage to the blank 3 or product size fluctuations due to sudden speed changes.

[0040] When a high-precision pressure sensor (not shown in the figure) located inside the mold base 5 or near the forming hole at the lead-out end detects that the pressure inside the cavity has reached the fourth preset pressure P4 (this pressure value indicates that the forming hole at the lead-out end is completely filled, and is usually set to 1.1-1.3 times P2), the control system determines that the forming process is complete. At this time, the main hydraulic cylinder 4 and the auxiliary hydraulic cylinder 8 simultaneously enter the pressure holding state, maintaining the current pressure for T seconds (T is preferably 3-8 seconds, specifically determined according to the product volume and material characteristics). The purpose of pressure holding is to replenish the small volume loss caused by the elastic aftereffect shrinkage of the metal or temperature changes (extrusion heating), ensuring the final dimensional accuracy and shape stability of the product.

[0041] Step 5: Sequential pressure release and demolding After the holding time is completed, perform sequential pressure release and demolding operations to prevent the product from deforming due to the sudden release of internal stress. First, the auxiliary hydraulic cylinder 8 depressurizes and returns, driving the side pusher 6 to move away from the billet 3. In the initial stage of the side pusher 6's movement, the spring on the outer side of the compressed spring rod 10 begins to expand and reset, pushing the side pusher 6 back smoothly until the spring rod 10 is completely disengaged from the damping sleeve 11 or reaches the preset reset position. This process effectively prevents the side pusher 6 from rigidly colliding with the side wall of the frame 1 at the end of its return stroke, protecting the equipment's accuracy.

[0042] After a delay of Δt (Δt is preferably 0.5-2 seconds, which ensures that the side pusher 6 has completely detached from the blank 3 and that the lateral force has been completely released), the main hydraulic cylinder 4 depressurizes and returns, driving the upper mold assembly to move upward and open the mold.

[0043] Finally, the ejection mechanism (not shown in the figure) located at the bottom of the frame 1 or below the worktable is activated. The ejector rod smoothly ejects the finished copper alloy plate with the lead-out end from the lower mold cavity, and it is then taken away by the operator or robot arm, thus completing a complete work cycle.

[0044] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A copper alloy thick plate lead-out end forming device based on cold extrusion process, comprising a frame (1) and a main hydraulic cylinder (4) and a die holder (5) mounted on the frame (1), the die holder (5) having a forming cavity for accommodating a blank (3), characterized in that, Also includes: The side pusher (6) is movably disposed on the side end of the frame (1), and the end of the side pusher (6) is provided with a long handle arm (12) for abutting or fastening connection with the side edge of the blank (3). A secondary hydraulic cylinder (8) is installed on the side end of the frame (1), and its piston rod is connected to the side push frame (6) for driving the side push frame (6) to move towards the billet (3); While the main hydraulic cylinder (4) drives the upper die to apply the main extrusion force to the blank (3), the auxiliary hydraulic cylinder (8) drives the side pusher (6) to apply the lateral thrust to the blank (3) through the long handle arm (12) so as to force the metal of the blank (3) to fill towards the forming hole at the lead-out end.

2. The copper alloy thick plate lead-out end forming device based on cold extrusion process according to claim 1, characterized in that: The end of the long handle (12) is provided with a notch that matches the side edge contour of the blank (3), and the notch is engaged with the blank (3) when the side pusher (6) moves.

3. The copper alloy thick plate lead-out end forming device based on cold extrusion process according to claim 1, characterized in that: The side wall of the frame (1) is provided with a transverse groove (9) through which the side pusher (6) passes. The transverse groove (9) guides and limits the movement of the side pusher (6).

4. The copper alloy thick plate lead-out end forming device based on cold extrusion process according to claim 1, characterized in that: An extension plate (7) is provided on the frame (1). A lateral stabilizing mechanism is connected between the extension plate (7) and the side push frame (6). The lateral stabilizing mechanism includes a spring rod (10) and a damping sleeve (11). One end of the spring rod (10) is connected to the side push frame (6), and the other end is movably inserted into the damping sleeve (11). A spring is sleeved on the outside of the spring rod (10).

5. The copper alloy thick plate lead-out end forming device based on cold extrusion process according to claim 4, characterized in that: The damping sleeve (11) is fixedly embedded inside the extension plate (7). When the spring rod (10) moves with the side pusher (6), it compresses the spring and inserts into the damping sleeve (11) to absorb the impact of lateral movement and realize the smooth reset of the side pusher (6).

6. A method for forming the lead-out end of a thick copper alloy plate based on cold extrusion technology, implemented using the apparatus described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Place the pre-treated blank (3) into the lower mold cavity of the mold base (5), and keep the long handle arm (12) at the end of the side pusher (6) and the side edge of the blank (3) at the initial gap. Step 2: Start the main hydraulic cylinder (4) to drive the upper mold downward, close the cavity and apply the first preset pressure to the blank (3) so that the blank (3) fits the bottom surface of the mold cavity, while the auxiliary hydraulic cylinder (8) remains locked. Step 3: The main hydraulic cylinder (4) continues to pressurize to the second preset pressure. At the same time, the auxiliary hydraulic cylinder (8) is started to drive the side pusher (6) to move towards the billet (3), so that the long handle arm (12) grabs the side edge of the billet (3) and applies the third preset pressure. The application time of the second preset pressure and the third preset pressure overlaps, forming a bidirectional extrusion effect. Step 4: When the pressure inside the cavity reaches the fourth preset pressure, the main hydraulic cylinder (4) and the auxiliary hydraulic cylinder (8) simultaneously enter the pressure holding state and maintain the pressure for T seconds. Step 5: First, the auxiliary hydraulic cylinder (8) depressurizes and returns. After a delay of Δt time, the main hydraulic cylinder (4) depressurizes and opens the mold. Finally, the ejection mechanism ejects the molded finished product.

7. The method for forming the lead-out end of a thick copper alloy plate based on cold extrusion process according to claim 6, characterized in that: In step one, the initial gap is 0.5-2mm, which is used to ensure that the side pusher (6) can quickly contact the blank (3) when it moves, and at the same time avoid positional displacement before mold closing.

8. The method for forming the lead-out end of a thick copper alloy plate based on cold extrusion process according to claim 6, characterized in that: In step two, the first preset pressure is 30%-50% of the yield strength of the blank (3) material, which is used to achieve the initial bonding and venting of the blank (3).

9. The method for forming the lead-out end of a thick copper alloy plate based on cold extrusion process according to claim 6, characterized in that: In step three, the direction of the third preset pressure is consistent with the direction of metal flow towards the lead-out end forming hole, and the overlap time between the second preset pressure and the third preset pressure covers at least the process of metal filling the far end of the lead-out end forming hole.

10. The method for forming the lead-out end of a thick copper alloy plate based on cold extrusion process according to claim 6, characterized in that: In step four, the fourth preset pressure is set to 1.1-1.3 times the second preset pressure, and the pressure holding time T is 3-8 seconds; in step five, the delay time Δt is 0.5-2 seconds, which is used to ensure that the lateral force is completely released before mold opening.

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