Copper wire continuous drawing densification method and system

Abstract

The invention relates to the technical field of metal processing, in particular to a continuous drawing densification method and system for a copper wire. A first cooling medium is introduced into the cooling liquid flow channel along with the drawing process, and the temperature difference of the first cooling medium is continuously monitored; when the temperature difference is smaller than a set threshold value, the temperature of the first cooling medium is lowered, meanwhile, a spraying device is started, and a second cooling medium is sprayed to the copper wire moving out of the drawing die; wherein the second cooling medium temperature is lower than the first cooling medium temperature, and the first cooling medium temperature is higher than the second cooling medium temperature after being reduced. By monitoring the inlet and outlet temperature difference and setting the threshold value, the thermal load state of the cooling system can be accurately judged, and energy waste or insufficient cooling of a traditional fixed cooling mode is avoided; when the temperature difference is lower than a threshold value, double cooling is triggered in a linkage mode, the heat management bottleneck of a single cooling mode is broken through, it is guaranteed that softening is blocked in the copper wire drawing process, and the densification effect is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of metal processing, and in particular to a method and system for continuous drawing and densification of copper wire. Background Art

[0002] Continuous drawing can close internal defects of copper wire, thereby improving the density of its microstructure and enhancing its mechanical properties.

[0003] During drawing, the copper wire rubs violently against the inner wall of the die, generating frictional heat. During plastic deformation, the energy consumed by lattice slip and dislocation motion is partially converted into deformation heat. If the cooling system is inefficient, this frictional and deformation heat cannot be dissipated in time, causing the local temperature of the copper wire to rise significantly. Copper's strength and yield stress decrease exponentially with increasing temperature. At high temperatures, atomic mobility increases, dislocation slip resistance decreases, and the material undergoes thermal softening.

[0004] Closing internal defects such as holes and microcracks requires high hydrostatic pressure, that is, three-dimensional compressive stress, the sources of which include the radial compression force of the mold on the copper wire and the lateral pressure converted from the axial pulling force; after the material softens, the pulling force required for the same deformation is reduced, and the radial compressive force is simultaneously weakened. At high temperatures, the fluidity of copper is enhanced, and stress is more easily released through plastic relaxation, and the hydrostatic pressure level decreases, resulting in insufficient driving force for pressing defects. In this case, the densification goal to be achieved by drawing is often unattainable. Summary of the Invention

[0005] The present invention provides a method and system for continuous drawing and densification of copper wire, which can effectively solve the problems in the background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A method for continuous drawing and densification of copper wire, comprising: Setting a coolant flow channel in the drawing die; During the drawing process, a first cooling medium is introduced into the cooling liquid flow channel, and a temperature difference of the first cooling medium at an outlet and an inlet of the cooling liquid flow channel is continuously monitored; When the temperature difference is less than a set threshold, the temperature of the first cooling medium is reduced, and at the same time, a spray device is opened at the outlet of the drawing die to spray a second cooling medium onto the copper wire moving out of the drawing die; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

[0007] Furthermore, the first cooling medium and the second cooling medium are the same medium, and the temperature of the first cooling medium is reduced by mixing with the second cooling medium.

[0008] Furthermore, when the temperature difference is less than a set threshold, the action of lowering the temperature of the first cooling medium is performed after 0.1 to 2 seconds.

[0009] A copper wire continuous drawing and densification system, comprising: The drawing die is provided with a coolant flow channel for circulating a first cooling medium; a temperature monitoring module for monitoring a temperature difference between the first cooling medium at the outlet and the inlet of the coolant flow channel; a spraying device, provided at the outlet of the drawing die, for spraying a second cooling medium onto the copper wire; a control module, which obtains the temperature difference and, when the temperature difference is less than a set threshold, issues a cooling command for the first cooling medium and simultaneously activates the spray device; The medium supply module provides a first cooling medium and a second cooling medium respectively; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

[0010] Furthermore, the first cooling medium and the second cooling medium are made of the same material; The drawing die is further provided with an auxiliary medium flow channel, which is connected to the coolant flow channel; The auxiliary medium flow channel is used to introduce the second cooling medium into the coolant flow channel to reduce the temperature of the first cooling medium in the flow channel.

[0011] Furthermore, when the temperature difference is less than a set threshold, a cooling command for the first cooling medium is issued after 0.1 to 2 seconds.

[0012] Furthermore, the coolant flow channel includes at least two circulation branches, one end of each circulation branch is connected through a first annular branch, and the other end is connected through a second annular branch, and the first annular branch and the second annular branch are connected to the inlet and the outlet respectively; The drawing die is further provided with an auxiliary medium flow channel, which is an annular flow channel coaxial with and connected to the first annular branch and has an annular open end; The spray device is an annular structure with a protruding stop ring, the side wall of which is snugly embedded in the auxiliary medium flow channel, and the third annular branch inside the spray device is connected to the spray position and the auxiliary medium flow channel through the first hole and the second hole respectively; When the second cooling medium flows into the third annular branch, the spray device opens the connecting position between the second hole and the auxiliary medium flow channel by moving relative to the drawing die, otherwise the connecting position is closed.

[0013] Furthermore, the drawing die includes a main body, and an inner ring body and an outer ring body provided at one end of the main body; A first annular branch and an auxiliary medium flow channel are formed between the inner ring body and the outer ring body through a step surface transition; The second hole in the spray device is arranged toward the step surface. When the spray device is in contact with the step surface, the second hole is blocked by the step surface to close the communication position.

[0014] Furthermore, the second cooling medium flowing out from the second hole exerts pressure on the step surface, and the spray device moves under the reaction force to open the connecting position.

[0015] Furthermore, a limiting device and a resetting device are provided between the drawing die and the spraying device; The limiting device is used to limit the maximum movement distance of the spraying device relative to the drawing die; When the spraying stops, the reset device applies force to the spray device relative to the drawing die to reset the device so as to close the communication position.

[0016] The technical solution of the present invention can achieve the following technical effects: In the present invention, by monitoring the temperature difference between the inlet and outlet of the cooling medium and setting a threshold, the heat load state of the cooling system can be accurately determined, avoiding energy waste or insufficient cooling in the traditional fixed cooling mode; when the temperature difference is lower than the threshold, double cooling is triggered in conjunction, breaking through the thermal management bottleneck of a single cooling method, ensuring that the copper wire is always in a suitable temperature window during the drawing process, ensuring that the copper wire is blocked from softening during the drawing process, and ensuring the densification effect.

[0017] In the double cooling process, the temperature of the first cooling medium is first lowered to appropriately increase the heat absorption of the front channel, thereby sharing the cooling pressure of the rear channel and realizing heat load redistribution. On the one hand, it can effectively reduce the cooling consumption of the spray device, and on the other hand, it can avoid the risk of thermal shock. By reducing the temperature fluctuation amplitude of the copper wire through graded cooling, the internal stress concentration of the material is reduced, and the micro cracks on the surface of the copper wire due to sudden cooling are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1This is a flow chart of the method for continuous drawing and densification of copper wire in Example 1; Figure 2 This is a framework diagram of the copper wire continuous drawing and densification system in Example 2; Figure 3 It is a schematic diagram of the combined structure of the drawing die and the spray device; Figure 4 for Figure 3 Schematic diagram of the decomposition of the combined structure at the first angle; Figure 5 for Figure 3 Schematic diagram of the decomposition of the composite structure at the second angle; Figure 6 It is a structural diagram of the drawing die (including partial cross-section); Figure 7 It is a structural diagram of the distribution plate in the spray device; Figure 8 is a schematic diagram of the mixing process of the first cooling medium and the second cooling medium; Figure 9 A schematic diagram showing the connection position from closed to open; Figure 10 for Figure 9 A partial enlarged view of point A in the middle; Reference numerals: 1. Drawing die; 2. Spraying device; 11. Circulation branch; 12. First annular branch; 13. Second annular branch; 14. Auxiliary medium flow channel; 15. Inlet; 16. Outlet; 17. Base; 18. End cover; 19. Inner ring; 110. Outer ring; 111. Step surface; 112. Magnetic ring; 21. Stop ring; 22. Third annular branch; 23. First hole position; 24. Second hole position; 25. Distribution plate; 26. Cover body. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Example 1: like Figure 1 As shown, a copper wire continuous drawing and densification method comprises: Setting a coolant flow channel in the drawing die; During the drawing process, a first cooling medium is introduced into the cooling liquid flow channel, and a temperature difference of the first cooling medium at an outlet and an inlet of the cooling liquid flow channel is continuously monitored; When the temperature difference is less than the set threshold, the temperature of the first cooling medium is reduced, and at the same time, a spray device is turned on at the outlet of the drawing die to spray the second cooling medium onto the copper wire moving out of the drawing die; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

[0022] In this embodiment, by monitoring the temperature difference between the inlet and outlet of the cooling medium and setting a threshold, the cooling system's thermal load can be accurately determined, avoiding the energy waste or insufficient cooling associated with traditional fixed cooling modes. When the temperature difference falls below the threshold, dual cooling is triggered, breaking through the thermal management bottleneck of a single cooling method and ensuring that the copper wire remains within the optimal temperature window during the drawing process. Specifically, internal cooling in the mold absorbs the heat generated during the drawing process, suppressing frictional heat and deformation heat sources. When this cooling effect is insufficient, spray cooling directly acts on the copper wire surface to eliminate residual heat and prevent softening.

[0023] Under normal working conditions, cooling is only performed through the coolant flow channel, and it can work in a relatively energy-saving mode. Under high heat load conditions, double cooling is achieved. In the double cooling process, the temperature of the first cooling medium is first lowered to appropriately increase the heat absorption of the front channel, thereby sharing the cooling pressure of the rear channel and realizing heat load redistribution. On the one hand, it can effectively reduce the cooling consumption of the spray device, and on the other hand, it can avoid the risk of thermal shock. The temperature fluctuation amplitude of the copper wire can be reduced by graded cooling, the internal stress concentration of the material can be reduced, and the micro cracks on the surface of the copper wire due to sudden cooling can be reduced.

[0024] In specific implementation, the setting threshold of the temperature difference, the determination of the first cooling medium temperature and the second cooling medium temperature must be based on the thermodynamic principles and the linkage design of process parameters, and can also be fine-tuned by referring to the empirical values ​​already used in actual production.

[0025] As a preference of the above embodiment, the first cooling medium and the second cooling medium are the same medium, and the temperature of the first cooling medium is reduced by mixing with the second cooling medium.

[0026] Based on this optimization method, the heat exchange efficiency can be improved. Homogeneous media have no phase change interference, which can avoid the attenuation of heat transfer efficiency caused by the mixing of heterogeneous media and maintain the stability of heat conduction in the cooling channel. Using the same medium can adopt a single medium circulation system, and only the branches with different temperatures need to be controlled, thereby simplifying the cooling medium supply architecture and reducing equipment maintenance costs. The mixing method can realize the rapid adjustment of the temperature of the first cooling medium to adapt to the dynamic heat load changes in the drawing process.

[0027] During implementation, the first cooling medium and the second cooling medium can be selected from deionized water-based corrosion inhibitors. Of course, this is just a conventional choice. Other media that meet the use requirements under specific circumstances are also within the scope of protection of the present invention.

[0028] As a preferred embodiment of the above, when the temperature difference is less than the set threshold, the action of lowering the temperature of the first cooling medium is performed after 0.1 to 2 seconds, thereby avoiding false triggering caused by transient thermal interference. Sudden fluctuations in local friction heat during the drawing process, such as copper chips stuck in the die, may cause the temperature difference to decrease instantaneously, but the continuous cooling failure state is not actually reached. By delaying and filtering the transient interference, the triggering action only responds to continuous thermal load exceeding the limit.

[0029] Example 2 like Figure 2 As shown, a copper wire continuous drawing and densification system comprises: The drawing die is provided with a coolant flow channel for circulating a first cooling medium; A temperature monitoring module monitors the temperature difference between the first cooling medium at the outlet and the inlet of the coolant flow channel; A spraying device is provided at the outlet of the drawing die and is used to spray the second cooling medium onto the copper wire; The control module obtains the temperature difference and issues a cooling command for the first cooling medium when the temperature difference is less than a set threshold. The cooling can be achieved by activating a cooling device, such as a heat exchanger, and activating a spray device at the same time. The medium supply module provides a first cooling medium and a second cooling medium respectively; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

[0030] In this embodiment, the first cooling medium and the second cooling medium are made of the same material; the drawing die is also provided with an auxiliary medium flow channel, which is connected to the coolant flow channel; the auxiliary medium flow channel is used to introduce the second cooling medium into the coolant flow channel to reduce the temperature of the first cooling medium in the flow channel.

[0031] As a preference of this embodiment, when the temperature difference is less than a set threshold, a temperature reduction command for the first cooling medium is issued after 0.1 to 2 seconds.

[0032] The technical effects achieved by this embodiment are the same as those of the first embodiment and will not be described again here.

[0033] Example 3 The main system form of this embodiment is the same as that of the second embodiment, except that the drawing die and the spraying device adopt the following structural form: like Figures 3 to 10As shown, the coolant flow channel includes at least two flow branches 11, one end of each flow branch 11 is connected through a first annular branch 12, and the other end is connected through a second annular branch 13, and the first annular branch 12 and the second annular branch 13 are connected to the inlet 15 and the outlet 16 respectively; during implementation, the movement direction of the copper wire is opposite to the setting direction of the inlet 15 and the outlet 16, thereby ensuring that the first cooling medium and the copper wire are heat exchanged in the opposite direction; The drawing die 1 is further provided with an auxiliary medium flow channel 14, which is an annular flow channel coaxial with and connected to the first annular branch 12 and has an annular open end; The spray device 2 is an annular structure and has a protruding stop ring 21. The side wall of the stop ring 21 is fitly embedded in the auxiliary medium flow channel 14. The third annular branch 22 inside the spray device 2 is connected to the spray position and the auxiliary medium flow channel 14 through the first hole 23 and the second hole 24 respectively; the flow path direction and number of the first hole 23 and the second hole 24 can be set according to actual needs.

[0034] When the second cooling medium flows into the third annular branch 22 , the spray device 2 opens the connection position between the second hole 24 and the auxiliary medium flow channel 14 by moving relative to the drawing die 1 , otherwise the connection position is closed.

[0035] This preferred solution provides a partial system structure that can achieve the temperature reduction of the first cooling medium by mixing with the second cooling medium in Example 1. The combined structure of the drawing die 1 and the spraying device 2 allows for simultaneous mixing and spraying of the second cooling medium with the first cooling medium. Specifically, under normal circumstances, the first cooling medium circulates normally. When the second cooling medium does not flow into the third annular branch 22, the connection between the second hole 24 and the auxiliary medium flow channel 14 is closed, and the first annular branch 12 is relatively closed.

[0036] When the second cooling medium flows in and pressure is obtained in the third annular branch 22, on the one hand, the third annular branch 22 supplies coolant to the spray position through the first hole 23, and on the other hand, the connecting position is opened, and the second cooling medium flowing in through the second hole 24 will be mixed with the first cooling medium through the auxiliary medium flow channel 14 and the first annular branch 12, thereby achieving the technical effect to be achieved in the above-mentioned embodiment 1.

[0037] As a preferred embodiment of the above embodiment, the drawing die 1 includes a main body, and an inner ring body 19 and an outer ring body 110 provided at one end of the main body; A first annular branch 12 and an auxiliary medium flow channel 14 are formed between the inner ring body 19 and the outer ring body 110 through a step surface 111; The second hole 24 in the spray device 2 is arranged toward the step surface 111 . When the spray device 2 is in contact with the step surface 111 , the second hole 24 is blocked by the step surface 111 and the communication position is closed.

[0038] This embodiment provides a specific structural form. The main body comprises an end cap 18 and a base 17, which respectively provide a second annular branch 13 and a flow branch 11. An inner ring body 19 and an outer ring body 110 are fixed to the main body. The coaxial first annular branch 12 and auxiliary medium flow channel 14 formed in the middle accommodate the open end of the flow branch 11. The spray device 2 is obtained by combining a distribution plate 25 with a stop ring 21 and a cover body 26, forming a third annular branch 22 between them. This separate structure ensures the workability of the product structure.

[0039] During installation, the flow-stop ring 21 of the spray device 2 is inserted into the auxiliary medium flow channel 14 through the annular open end of the auxiliary medium flow channel 14. The sidewalls are in a sealed fit with the sidewalls of the auxiliary medium flow channel 14. This sealing relationship must not be disrupted by the movement of the spray device 2 relative to the drawing die 1, thereby preventing leakage of the second cooling medium. After the above installation process is completed, the auxiliary medium flow channel 14 can guide the movement of the spray device 2 through the sidewalls, thereby ensuring its stable movement and facilitating smoother opening and closing of the connecting position.

[0040] As the optimal way to open the connecting position, the second cooling medium flowing out from the second hole 24 applies pressure to the step surface 111, and the spray device 2 moves under the reaction force to open the connecting position.

[0041] This method does not require any additional power, which can effectively reduce the cost of implementation. Figure 8 As shown, a schematic diagram of the mixing process of the first cooling medium and the second cooling medium is shown. Figure 9 A schematic diagram showing the connection position from closed to open is shown in FIG.

[0042] Of course, in order to better realize the above-mentioned optimization method, a limiting device and a reset device are provided between the drawing die 1 and the spray device 2; the limiting device is used to limit the maximum movement distance of the spray device 2 relative to the drawing die 1; when the spraying is stopped, the reset device applies force to the spray device 2 relative to the drawing die 1 to reset it to close the connected position.

[0043] In this preferred embodiment, a limiting device is provided to ensure the stability of the combined structure of the drawing die 1 and the spray device 2 and avoid separation. As for the structure of the limiting device, there are a variety of forms available in the prior art. For example, a mechanical blocking structure is fixedly provided on the drawing die 1. When the spray device 2 moves to the extreme position, it stops moving by touching the mechanical blocking structure.

[0044] As for the reset device, since there is no need for stepless adjustment of the movement distance in this embodiment, it is only necessary to switch between closing and opening at a set distance. Therefore, a magnetic structure can be adopted. For example, a magnetic ring body 112 is respectively provided on the end faces of the outer ring body 110 and the distribution plate 25 facing each other. The magnetic size can be such that the second cooling medium flowing out of the second hole 24 can press the step surface 111 to open the connecting position. When the pressure is released, the two are made to fit together through magnetic adsorption, and the connecting position is closed. Of course, this is only an example of the structural form of the reset device. Methods such as spring reset are also within the protection scope of the present invention.

[0045] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for continuous drawing and densification of copper wire, characterized in that: include: Setting a coolant flow channel in the drawing die; During the drawing process, a first cooling medium is introduced into the cooling liquid flow channel, and a temperature difference of the first cooling medium at an outlet and an inlet of the cooling liquid flow channel is continuously monitored; When the temperature difference is less than a set threshold, the temperature of the first cooling medium is reduced, and at the same time, a spray device is opened at the outlet of the drawing die to spray a second cooling medium onto the copper wire moving out of the drawing die; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

2. The method for continuous drawing and densification of copper wire according to claim 1, characterized in that: The first cooling medium and the second cooling medium are the same medium, and the temperature of the first cooling medium is reduced by mixing with the second cooling medium.

3. The method for continuous drawing and densification of copper wire according to claim 1, characterized in that: When the temperature difference is less than a set threshold, the action of lowering the temperature of the first cooling medium is performed after 0.1 to 2 seconds.

4. A copper wire continuous drawing and densification system, characterized in that: include: The drawing die is provided with a coolant flow channel for circulating a first cooling medium; a temperature monitoring module for monitoring a temperature difference between the first cooling medium at the outlet and the inlet of the coolant flow channel; a spraying device, provided at the outlet of the drawing die, for spraying a second cooling medium onto the copper wire; a control module, which obtains the temperature difference and, when the temperature difference is less than a set threshold, issues a cooling command for the first cooling medium and simultaneously activates the spray device; The medium supply module provides a first cooling medium and a second cooling medium respectively; The temperature of the second cooling medium is lower than the temperature of the first cooling medium, and the temperature of the first cooling medium is higher than the temperature of the second cooling medium after it is lowered.

5. The copper wire continuous drawing and densification system according to claim 4, characterized in that: The first cooling medium and the second cooling medium are made of the same material; The drawing die is further provided with an auxiliary medium flow channel, which is connected to the coolant flow channel; The auxiliary medium flow channel is used to introduce the second cooling medium into the coolant flow channel to reduce the temperature of the first cooling medium in the flow channel.

6. The copper wire continuous drawing and densification system according to claim 4, characterized in that: When the temperature difference is less than a set threshold, a temperature reduction command for the first cooling medium is issued after 0.1 to 2 seconds.

7. The copper wire continuous drawing and densification system according to claim 4, characterized in that: The coolant flow channel includes at least two circulation branches, one end of each circulation branch is connected through a first annular branch, and the other end is connected through a second annular branch, and the first annular branch and the second annular branch are connected to the inlet and the outlet respectively; The drawing die is further provided with an auxiliary medium flow channel, which is an annular flow channel coaxial with and connected to the first annular branch and has an annular open end; The spray device is an annular structure with a protruding stop ring, the side wall of which is snugly embedded in the auxiliary medium flow channel, and the third annular branch inside the spray device is connected to the spray position and the auxiliary medium flow channel through the first hole and the second hole respectively; When the second cooling medium flows into the third annular branch, the spray device opens the connecting position between the second hole and the auxiliary medium flow channel by moving relative to the drawing die, otherwise the connecting position is closed.

8. The copper wire continuous drawing and densification system according to claim 7, characterized in that: The drawing die includes a main body, and an inner ring body and an outer ring body provided at one end of the main body; A first annular branch and an auxiliary medium flow channel are formed between the inner ring body and the outer ring body through a step surface transition; The second hole in the spray device is arranged toward the step surface. When the spray device is in contact with the step surface, the second hole is blocked by the step surface to close the communication position.

9. The copper wire continuous drawing and densification system according to claim 8, characterized in that: The second cooling medium flowing out from the second hole exerts pressure on the step surface, and the spray device moves under the reaction force to open the connecting position.

10. The copper wire continuous drawing and densification system according to claim 8, characterized in that: A limiting device and a reset device are provided between the drawing die and the spraying device; The limiting device is used to limit the maximum movement distance of the spraying device relative to the drawing die; When the spraying stops, the reset device applies force to the spray device relative to the drawing die to reset the device so as to close the communication position.

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