Preparation method of tin foil

Abstract

This application provides a method for preparing tin foil, relating to the field of metal processing technology. The method includes hot rolling an initial workpiece at least three times to obtain a final workpiece. The initial workpiece is tin strip. This application provides a method for preparing tin foil by performing at least three hot rolling processes to progressively compress the initial workpiece, causing its thickness to decrease continuously. During these multiple hot deformation processes, work hardening is effectively mitigated, and the material's good ductility is maintained, thereby obtaining an ultra-thin, continuous tin foil with excellent surface quality. Because the tin strip maintains good ductility after each hot rolling pass, unlike traditional cold rolling processes which require downtime, transfer, and prolonged annealing, the entire thinning process can be carried out continuously and uninterruptedly. This effectively accelerates the production cycle and improves overall preparation efficiency.

Description

Technical Field

[0001] This application relates to the technical field of metal processing, and more particularly to a method for preparing tin foil. Background Technology

[0002] Ultra-thin tin strips have a wide range of applications in new energy, flexible electronics, micro sensors, and high-end semiconductor packaging.

[0003] In related technologies, the preparation of ultrathin metal foils often employs a process route of multiple rolling and intermediate heat treatment. By controlling the compression ratio of each rolling pass, the foil is annealed after each rolling pass to eliminate work hardening before proceeding to the next rolling pass, ultimately achieving the target thickness.

[0004] However, existing tin strips suffer from low manufacturing efficiency. Summary of the Invention

[0005] This application provides a method for preparing tin foil, which improves the preparation efficiency.

[0006] This application provides a method for preparing tin foil, the method comprising:

[0007] The initial workpiece is hot-rolled at least three times to obtain the final workpiece.

[0008] The initial state of the workpiece is tin strip.

[0009] In one possible embodiment, the hot rolling temperature is T, where T satisfies: 35℃≤T≤45℃.

[0010] In one possible embodiment, at least three hot rolling steps include an initial hot rolling step, an intermediate hot rolling step, and a final hot rolling step, wherein the intermediate hot rolling step is performed multiple times.

[0011] The hot rolling pressure in the initial hot rolling step is greater than that in the intermediate hot rolling step.

[0012] The hot rolling pressure at the end of the hot rolling step is greater than the hot rolling pressure at the beginning of the hot rolling step.

[0013] In one possible embodiment, each hot rolling cycle includes an unwinding step and an unwinding tension adjustment step, and each hot rolling cycle includes a winding tension adjustment step and a winding step.

[0014] In the unwinding tension adjustment step, the tension of the unwinding tension adjustment roller is greater than the tension of the winding tension adjustment roller in the winding tension adjustment step.

[0015] In one possible embodiment, the tension of the unwinding tension adjusting roller in the unwinding tension adjusting step before the previous hot rolling is greater than the tension of the unwinding tension adjusting roller in the unwinding tension adjusting step before the next hot rolling.

[0016] In one possible embodiment, the tension of the winding tension adjusting roller in the winding tension adjusting step after the previous hot rolling is greater than the tension of the winding tension adjusting roller in the winding tension adjusting step after the subsequent hot rolling.

[0017] In one possible embodiment, the method for preparing tin foil further includes a wrinkle removal step, which specifically includes:

[0018] After the hot rolling step is terminated and before the coiling tension adjustment step, the surface of the workpiece is inspected to identify the location of the bulges.

[0019] Along the direction of workpiece movement, cut off the portions on both sides of the raised position of the workpiece to obtain the final workpiece.

[0020] In one possible embodiment, the method for preparing tin foil further includes a lubrication step, which specifically includes:

[0021] After each unwinding tension adjustment step and before each hot rolling, a lubricant is sprayed onto the surface of the workpiece.

[0022] In one possible embodiment, the method for preparing tin foil further includes an auxiliary conveying step, which includes:

[0023] After the unwinding step, the workpiece is conveyed to the unwinding tension adjusting roller via the first auxiliary roller;

[0024] The workpiece, after being adjusted by the unwinding tension regulating roller, is conveyed to the hot rolling roll via the second auxiliary roller.

[0025] After hot rolling, the workpiece is conveyed to the winding tension adjusting roller via the third auxiliary roller;

[0026] The workpiece, after being adjusted by the winding tension regulating roller, is conveyed to the winding mechanism via the fourth auxiliary roller.

[0027] In one possible embodiment, performing at least three hot rolling cycles on the initial workpiece to obtain the final workpiece specifically includes:

[0028] After the initial state workpiece is unwound by the unwinding mechanism, it is sent to the unwinding tension regulating roller for tension adjustment to obtain the intermediate state workpiece a1; wherein, the tension of the unwinding tension regulating roller is F1;

[0029] Intermediate workpiece a1 is hot-rolled to obtain intermediate workpiece a2; the hot rolling pressure is M1.

[0030] The intermediate workpiece a2 is wound into the winding mechanism after the tension is adjusted by the winding tension adjusting roller to obtain the intermediate workpiece a; wherein, the tension of the winding tension adjusting roller is F2;

[0031] After the intermediate workpiece a is unwound by the unwinding mechanism, it is sent to the unwinding tension adjusting roller for tension adjustment to obtain the intermediate workpiece b1; wherein, the tension of the unwinding tension adjusting roller is F3;

[0032] Intermediate workpiece b1 is hot-rolled to obtain intermediate workpiece b2; the hot rolling pressure is M2.

[0033] The intermediate workpiece b2 is wound into the winding mechanism after the tension is adjusted by the winding tension adjusting roller to obtain the intermediate workpiece b; wherein, the tension of the winding tension adjusting roller is F4;

[0034] After the intermediate workpiece b is unwound by the unwinding mechanism, it is sent to the unwinding tension adjusting roller for tension adjustment to obtain the intermediate workpiece c1; wherein, the tension of the unwinding tension adjusting roller is F5;

[0035] Intermediate workpiece c1 is hot-rolled to obtain intermediate workpiece c2; the hot rolling pressure is M3.

[0036] The intermediate workpiece c2 is wound into the winding mechanism after the tension is adjusted by the winding tension adjusting roller to obtain the final workpiece; wherein, the tension of the winding tension adjusting roller is F6.

[0037] At least one of the following constraints must be met:

[0038] Hot rolling rolls are used to hot roll initial state workpiece, intermediate state workpiece a, and intermediate state workpiece b; the roll speed ratio of the hot rolling rolls is A, where A satisfies: 0.8≤A≤1;

[0039] The moving speed of the workpiece is B, and B satisfies: 1m / min≤B≤5m / min;

[0040] M1 satisfies: 7.5T≤M1≤8.5T;

[0041] M2 satisfies: 6.5T≤M2≤7.5T;

[0042] M3 satisfies: 12.5T ≤ M3 ≤ 13.5T;

[0043] F1 satisfies: 57N≤F1≤63N;

[0044] F2 satisfies: 17N≤F2≤23N;

[0045] F3 satisfies: 17N≤F3≤23N;

[0046] F4 satisfies: 6N≤F4≤10N;

[0047] F5 satisfies: 6N≤F5≤10N;

[0048] F6 satisfies: 4N≤F6≤6N.

[0049] The method for preparing tin foil provided in this application includes: hot rolling an initial workpiece at least three times to obtain a final workpiece. The initial workpiece is tin strip.

[0050] This application provides a method for preparing tin foil, which involves performing at least three hot rolling processes to progressively compress an initial workpiece, causing its thickness to decrease continuously. During multiple hot deformation processes, the method effectively alleviates work hardening and maintains the material's good ductility, thereby obtaining an ultra-thin, continuous tin foil with excellent surface quality.

[0051] In at least three hot rolling processes, the workpiece is kept above its recrystallization temperature so that the work hardening generated during rolling can be eliminated simultaneously by the dynamic recrystallization process.

[0052] Because the tin strip can maintain good ductility after each hot rolling pass, there is no need to stop the machine, transfer it, and perform a long annealing process as required by the traditional cold rolling process. The entire thinning process can be carried out continuously and without interruption.

[0053] The above-described method for preparing tin foil reduces equipment usage (eliminating the need for multiple annealing furnaces), lowers material transfer frequency and waiting time, thereby effectively accelerating the production cycle and improving overall preparation efficiency. Attached Figure Description

[0054] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0055] Figure 1 A flowchart illustrating a method for preparing tin foil as provided in an embodiment of this application;

[0056] Figure 2 The apparatus corresponding to the tin foil preparation method provided in the embodiments of this application Figure 1 ;

[0057] Figure 3 The apparatus corresponding to the tin foil preparation method provided in the embodiments of this application Figure 2 ;

[0058] Figure 4 A graph showing the experimental data on the relationship between sprayed silicone oil and roll forming thickness;

[0059] Figure 5 The graph shows the experimental data on the relationship between roll speed ratio and roll thickness.

[0060] Figure 6 A graph showing the experimental data on the relationship between belt speed and roll thickness;

[0061] Figure 7 A graph showing the experimental data on the relationship between roll forming temperature and roll forming thickness;

[0062] Figure 8 The graph shows the experimental data relating tension magnitude to roll thickness.

[0063] Explanation of reference numerals in the attached figures:

[0064] 100. Unwinding mechanism; 101. First auxiliary roller; 102. Unwinding tension adjusting roller; 103. Second auxiliary roller; 104. Silicone oil spraying mechanism; 105. Roller press; 106. Wrinkle removal mechanism; 107. Third auxiliary roller; 108. Rewinding tension adjusting roller; 109. Fourth auxiliary roller; 110. Rewinding mechanism.

[0065] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0066] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0067] Ultra-thin tin foil preparation technology belongs to the field of metal plastic processing and electronic material manufacturing, and is mainly used in applications such as photovoltaic cell interconnection, flexible electronic conductive connection, high-end electronic packaging and lightweight conductive components.

[0068] In the above scenario, tin strip is usually used as the base material for subsequent thinning processes. It needs to be continuously rolled to form ultra-thin tin foil that meets the requirements for thickness, conductivity, ductility and surface flatness.

[0069] In related technologies, the preparation of ultrathin metal foils often adopts a process route of multiple rolling and intermediate heat treatment.

[0070] For example, using 1mm thick metal strip as raw material, by controlling the compression ratio of each rolling (such as 2-6 times), the foil is annealed after each rolling pass to eliminate work hardening before entering the next rolling pass, and finally the target thickness is obtained.

[0071] Existing methods for preparing ultra-thin metal strips, especially tin strips to tin foil, typically employ a multi-pass rolling process combined with heat treatment. This involves gradually thinning the initial, thicker strip, relieving work hardening through heat treatment after each stage of thinning, and then continuing with subsequent rolling processes to ultimately achieve the target thickness.

[0072] The basic principle of this type of scheme is to use rolls to apply compression deformation to the strip, so that the material thickness decreases one by one. However, as the thickness decreases, the material is prone to work hardening after repeated plastic deformation, which leads to a decrease in ductility and an increase in deformation resistance. As a result, it is necessary to reduce the single-pass reduction and increase the number of rolling passes.

[0073] This results in a complex process involving alternating rolling and heat treatment. The entire production process is not only lengthy but also requires frequent switching of processes, leading to increased equipment occupancy time, slower production cycle, and higher energy consumption.

[0074] In summary, existing methods for preparing tin strips suffer from low production efficiency.

[0075] Therefore, this application provides a method for preparing tin foil, the method comprising: hot rolling an initial workpiece at least three times to obtain a final workpiece. The initial workpiece is tin strip.

[0076] This application provides a method for preparing tin foil, which involves performing at least three hot rolling processes to progressively compress an initial workpiece, causing its thickness to decrease continuously. During multiple hot deformation processes, the method effectively alleviates work hardening and maintains the material's good ductility, thereby obtaining an ultra-thin, continuous tin foil with excellent surface quality.

[0077] In at least three hot rolling processes, the workpiece is kept above its recrystallization temperature so that the work hardening generated during rolling can be eliminated simultaneously by the dynamic recrystallization process.

[0078] Because the tin strip can maintain good ductility after each hot rolling pass, there is no need to stop the machine, transfer it, and perform a long annealing process as required by the traditional cold rolling process. The entire thinning process can be carried out continuously and without interruption.

[0079] The above-described method for preparing tin foil reduces equipment usage (eliminating the need for multiple annealing furnaces), lowers material transfer frequency and waiting time, thereby effectively accelerating the production cycle and improving overall preparation efficiency.

[0080] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0081] Reference Figures 1 to 3 As shown in the embodiments of this application, a method for preparing tin foil is provided. The method for preparing tin foil includes:

[0082] The initial workpiece is subjected to at least three hot rolling processes to obtain the final workpiece.

[0083] For example, the initial state workpiece refers to the tin-based strip material that serves as the base material for subsequent thinning. The initial state workpiece can be a coiled tin strip, a sheet of tin strip, or a coiled tin-based semi-finished product. Its function is to provide a continuous, transportable, and highly ductile raw material for multi-pass hot rolling.

[0084] In one specific embodiment, the initial workpiece is a tin strip. Preferably, the initial workpiece is a tin strip with a thickness of 1 mm, wherein the tin content is not less than 99.99%.

[0085] Specifically, at least three hot rolling processes refer to hot rolling deformation treatment of tin strip in no less than three passes. In this way, the thickness of the strip is continuously reduced through progressive compression, and work hardening is alleviated and the ductility of the material is maintained during multiple hot deformation processes, thereby obtaining ultra-thin, continuous tin foil with good surface quality.

[0086] During at least three hot rolling processes, the workpiece remains above its recrystallization temperature. This means that work hardening generated during rolling can be eliminated simultaneously by the dynamic recrystallization process.

[0087] Because tin strip maintains good ductility after each hot rolling pass, it eliminates the need for downtime, relocation, and prolonged annealing as required by traditional cold rolling processes. The entire thinning process can be carried out continuously and without interruption. As a result, the tin strip process flow is simplified from the traditional cyclical pattern of "rolling, annealing, rolling, annealing..." to a continuous operation pattern of "hot rolling, hot rolling, hot rolling...".

[0088] The method for preparing this tin foil significantly reduces equipment usage (eliminating the need for multiple annealing furnaces), reduces material transfer frequency and waiting time, thereby effectively accelerating the production cycle and improving overall preparation efficiency.

[0089] As one feasible implementation method, an initial tin strip with a thickness of 1 mm and a tin content of not less than 99.99% is subjected to three consecutive hot rolling processes. The specific preparation method is as follows:

[0090] First hot rolling: The initial tin strip with a thickness of 1 mm is hot rolled for the first time to obtain a tin strip with a thickness of 40±3.8 μm, which is denoted as intermediate workpiece a.

[0091] The initial tin strip, originally 1mm thick, was thinned to 40μm in a single pass, achieving a thinning rate of up to 96%. This process rapidly approaches the target thickness level through extreme deformation, while simultaneously breaking down the initial casting structure through large deformation, thus providing uniform and fine-grained blanks for subsequent passes.

[0092] Second hot rolling: The intermediate workpiece a is subjected to a second hot rolling process to obtain a tin strip with a thickness of 20±2.0μm, denoted as intermediate workpiece b. In this embodiment, the second rolling is the roughing stage.

[0093] The 40μm intermediate tin strip is thinned to 20μm, a reduction rate of 50%. This step, as the roughing stage, uses a moderate amount of deformation to achieve a smooth thickness transition, while further releasing stress, homogenizing the microstructure, and preparing an ideal billet state for the final finishing rolling.

[0094] Third hot rolling: The intermediate workpiece b is subjected to a third hot rolling process to obtain a tin foil with a thickness of 10±2.4μm. In this embodiment, the third rolling is the finishing rolling stage.

[0095] The 20μm tin strip is precision rolled to a target thickness of 10μm, with a thinning rate of 50%. This step, known as the precision rolling stage, uses a larger rolling pressure for surface finishing and thickness fine-tuning, ultimately yielding an ultra-thin tin foil with a thickness of 10±2.4μm, a smooth surface, and ready for direct use.

[0096] After the above three hot rolling processes, the tin foil is the final workpiece and can directly enter the subsequent winding, slitting or laminating processes.

[0097] The tin foil preparation method provided in this application involves continuously hot rolling the tin strip at least three times above its recrystallization temperature, specifically reducing it directly from 1 mm to 10 ± 2.4 μm through three hot rollings without intermediate annealing. This simplifies the traditional "rolling and annealing" cycle into a continuous hot rolling operation, significantly reducing equipment occupation and material transfer, lowering energy consumption and production costs, and greatly improving preparation efficiency. At the same time, dynamic recrystallization effectively eliminates work hardening, ensuring that the tin strip always has good ductility, ultimately obtaining ultra-thin tin foil with uniform thickness, smooth surface, a thickness of up to 10 μm, and a purity of not less than 99.99%, meeting the requirements for subsequent winding, slitting, or lamination.

[0098] As one feasible implementation method, the hot rolling temperature is T, where T satisfies: 35℃≤T≤45℃.

[0099] For example, the recrystallization temperature of tin is much lower than room temperature (about -40°C). Within the hot rolling temperature range of 35-45°C, the atomic diffusion ability of tin is enhanced, and work hardening is almost instantly eliminated during or after deformation.

[0100] At temperatures of 35-45℃, tin's resistance to deformation decreases further, its ductility increases slightly, and it is far from reaching the temperature at which it softens and adheres. Therefore, compared to room temperature cold rolling, it can withstand a larger single-pass reduction, thereby reducing the total number of rolling passes and further shortening the process.

[0101] Because the temperature is much lower than the softening and adhesion temperature of tin, the problem of ultra-thin tin strips adhering to the rolls, causing strip breakage or surface damage, is avoided, thus ensuring the stability of the rolling process.

[0102] Meanwhile, tin hardly forms a visible oxide film on its surface within this temperature range, requiring no inert gas protection or special rolling solution, thus maintaining the metallic luster and excellent solderability of tin foil.

[0103] The method for preparing this tin foil does not require the heat-resistant seal, complex heating system, and protective atmosphere device of the high-temperature rolling mill 105. A conventional rolling mill with simple preheating and heat preservation accessories can meet the requirements.

[0104] After the final rolling pass is completed at 35-45℃, the tin foil is in a fully recrystallized or partially recrystallized state, with fine and uniform grains, low residual stress, and excellent bendability and surface flatness, meeting the needs of flexible electronic devices and semiconductor packaging.

[0105] In practice, the rolling system first preheats the hot rolling rolls and the area between the rolls, and uses temperature sensors to detect the temperature near the roll surface or roll gap in real time, so that the hot rolling temperature is stably maintained between 35°C and 45°C.

[0106] The tin strip undergoes at least three hot rolling passes within this temperature range, with the hot rolling rolls applying continuous and controlled compression deformation to the tin strip, causing its thickness to gradually decrease. Because the temperature is confined within a narrow range, the plastic flow state of the tin strip is more consistent in each pass, reducing problems such as increased brittleness and cracking caused by excessively low temperatures, as well as surface adhesion, deformation instability, or thickness fluctuations caused by excessively high temperatures.

[0107] In summary, controlling the hot rolling temperature within the range of 35℃ to 45℃ can improve the thinning efficiency while ensuring the stability of continuous tin strip processing, and is conducive to obtaining tin foil products with more uniform surface quality and higher thickness consistency.

[0108] As one feasible implementation, at least three hot rolling steps include an initial hot rolling step, an intermediate hot rolling step, and a final hot rolling step, wherein the intermediate hot rolling step is performed multiple times.

[0109] The hot rolling pressure in the initial hot rolling step is greater than the hot rolling pressure in the intermediate hot rolling step.

[0110] The hot rolling pressure at the end of the hot rolling step is greater than the hot rolling pressure at the beginning of the hot rolling step.

[0111] Specifically, the initial hot rolling step is a single rolling process, the purpose of which is to apply greater pressure to the initial state workpiece, i.e. the initial state tin strip, to achieve rapid and significant initial thinning in order to establish the geometric dimensions and initial microstructure required for subsequent rolling.

[0112] The initial tin strip is relatively thick, exhibiting strong resistance to deformation. Using higher pressure allows for efficient thinning in the first pass, rapidly reducing the thickness to a level suitable for fine rolling and minimizing the total number of rolling passes.

[0113] The large deformation caused by high pressure helps to break the initial casting structure, promotes subsequent recrystallization, and obtains fine and uniform grains.

[0114] The intermediate hot rolling step involves multiple rolling processes and is part of the roughing stage. The intermediate hot rolling step uses relatively low hot rolling pressure to steadily and controllably reduce the thickness of the tin strip, while fully releasing the internal stress of the material, alleviating work hardening, and reducing the accumulation of defects caused by continuous high-pressure rolling.

[0115] As the thickness decreases, the tin strip becomes increasingly sensitive to pressure and stress. Continuing to apply high pressure at this point can easily lead to edge cracks, wrinkles, or even strip breakage. Therefore, the hot rolling pressure in intermediate hot rolling steps is lower than that in the initial hot rolling step.

[0116] The intermediate hot rolling step reduces pressure, and the rough rolling strategy of "multiple passes and small deformation" allows the material more time to undergo static recrystallization after each pass, effectively releasing work hardening and maintaining excellent plasticity.

[0117] This method reduces the requirements for mill stiffness in each pass and accumulates a uniform deformation structure and dimensional consistency for the final finishing mill.

[0118] The final hot rolling step is a single rolling process, belonging to the finishing rolling stage. The final hot rolling step uses greater hot rolling pressure to perform final shaping and finishing of the tin strip surface, in order to obtain the target thickness, high surface flatness, and accurate dimensions.

[0119] Applying greater pressure in the final pass serves two purposes: first, it flattens and smooths out any minor surface imperfections accumulated in the previous passes, significantly reducing surface roughness; second, it allows for precise control of the high pressure to fine-tune the thickness of the finished product and lock in dimensional accuracy.

[0120] Applying greater pressure in the final pass can introduce a beneficial compressive stress state into the surface of the tin foil, which helps to improve its fatigue resistance and bending resistance.

[0121] In summary, by setting the hot rolling pressure of the initial hot rolling step to be greater than that of the intermediate hot rolling step, and the hot rolling pressure of the final hot rolling step to be greater than that of the initial hot rolling step, this method ensures the stability of the rolling process and reduces defects, while taking into account both efficient thinning (initial rolling step and final rolling step) and structural stress control (intermediate rolling step). It is suitable for preparing ultra-thin tin foils that require high flatness and high thickness consistency.

[0122] As one feasible implementation, each hot rolling process includes an uncoiling step and an uncoiling tension adjustment step before each hot rolling process, and a coiling tension adjustment step and a coiling step after each hot rolling process.

[0123] In the unwinding tension adjustment step, the tension of the unwinding tension adjustment roller 102 is greater than the tension of the winding tension adjustment roller 108 in the winding tension adjustment step.

[0124] Specifically, the unwinding tension regulating roller 102 refers to a tension control roller disposed at the unwinding end for applying pretension to the tin strip released from the unwinding mechanism 100 and stabilizing its conveying state. The unwinding tension regulating roller 102 is located between the unwinding mechanism 100 and the rolling mill 105 in the entire hot rolling production line.

[0125] The main function of the unwinding tension regulating roller 102 is to tighten the front end of the tin strip and correct its posture, so that the tin strip remains straight, centered and has sufficient anti-wrinkle ability before entering the hot rolling roll of the roller press 105, thereby reducing strip fluctuation, local wrinkles or unstable feeding caused by slack.

[0126] The winding tension adjusting roller 108 is a tension control roller installed at the rear end of the hot rolling mill, used to smoothly release and shape the output tension of the tin strip after one hot rolling. The winding tension adjusting roller 108 is located between the roller press 105 and the winding mechanism 110.

[0127] The main function of the winding tension regulating roller 108 is to maintain the stable traction state of the strip before winding, so that the final workpiece remains tightly interlayered, neat at the edges, and is not prone to tearing or crumbling during the rewinding process.

[0128] Specifically, the unwinding tension adjusting roller 102 and the winding tension adjusting roller 108 can be installed on independent tension control brackets. The brackets are fixedly connected to the frame or are adjustable. The two ends of the roller shaft are supported by bearing seats and form a torque input interface with the braking unit, servo motor, magnetic powder loader or damping mechanism to realize the controllable adjustment of the strip tension.

[0129] In one possible embodiment, both the unwinding tension adjusting roller 102 and the winding tension adjusting roller 108 can adopt a cylindrical roller structure with a mirror-finished steel surface to reduce friction on the solder strip surface and reduce the risk of scratches.

[0130] During the hot rolling process, the tin strip is unwound by the unwinding mechanism 100 and then enters the unwinding tension adjustment step. The unwinding tension adjustment roller 102 applies a relatively high traction tension to the tin strip according to the preset tension value and forms a stable front feed boundary with the subsequent hot rolling roller, so that the tin strip remains flat, centered and continuously fed before hot rolling.

[0131] The tin strip then enters the hot rolling mill and undergoes a thinning deformation. After leaving the hot rolling zone, it goes through a winding tension adjustment step. At this time, the winding tension adjustment roller 108 applies a relatively low tension to the strip to reduce edge warping, local stress concentration, or surface damage caused by excessive tension when the hot-rolled thin strip is rewound. After that, the strip enters the winding step to complete the winding.

[0132] Because the tension in the unwinding tension adjustment step is greater than that in the winding tension adjustment step, the tin strip forms a stable tension state before hot rolling, and after hot rolling, the excess stress is gradually released and the strip is smoothly rewound. This ensures that the tin strip is in a controllable stress environment before and after each hot rolling process, reducing the risk of wrinkles, deviations and strip breakage caused by tension fluctuations. It also helps maintain thickness consistency and surface flatness during multiple hot rolling processes.

[0133] As one feasible implementation, the tension of the unwinding tension regulating roller 102 in the unwinding tension regulating step before the previous hot rolling is greater than the tension of the unwinding tension regulating roller 102 in the unwinding tension regulating step before the next hot rolling.

[0134] In the previous hot rolling winding tension adjustment step, the tension of the winding tension adjustment roller 108 is greater than that in the subsequent hot rolling winding tension adjustment step.

[0135] In multi-pass hot rolling, the tension parameter exhibits a decreasing or graded control relationship as the pass progresses.

[0136] Specifically, the tension of the unwinding tension adjusting roller 102 before the previous hot rolling is greater than the tension of the unwinding tension adjusting roller 102 before the next hot rolling; similarly, the tension of the winding tension adjusting roller 108 after the previous hot rolling is greater than the tension of the winding tension adjusting roller 108 after the next hot rolling.

[0137] The purpose of this setting is to ensure that the tin strip has high introduction stability and deformation constraint in the previous pass (when it is thicker and has better rigidity); while in the subsequent pass (when the thickness is reduced, the rigidity decreases and work hardening accumulates), the conveying tension is reduced accordingly to reduce the occurrence of tearing, edge fluctuation, local wrinkling or deviation of the strip under high tension conditions, thereby maintaining the uniformity of stress throughout the hot rolling process.

[0138] During operation, before the tin strip enters the corresponding roll press 105 from the unwinding mechanism 100, the control system first sets the tension of the unwinding tension regulating roller 102 based on the thickness status of the current pass, the target thinning amount, and the material temperature information.

[0139] Before the previous hot rolling, the uncoiling tension regulating roller 102 maintains a relatively high tension to enhance the straightness and anti-disturbance ability of the tin strip as it enters that pass. Before the tin strip passes through this hot rolling pass and enters the subsequent pass, the system simultaneously reduces the tension of the uncoiling tension regulating roller 102 before the next pass and reduces the tension of the winding tension regulating roller 108 on the corresponding exit side, ensuring that the tension before or after the next hot rolling pass is less than the tension corresponding to the previous hot rolling pass. Thus, the tin strip obtains a stress environment that matches its decreasing rigidity during the gradual thinning process.

[0140] With the above settings, higher tension in the preceding passes helps to maintain stable bonding and speed synchronization of the strip when it enters the gap between the rolls; while lower tension in the subsequent passes can reduce the axial tensile stress on the tin strip in the ultra-thin state, reduce the probability of edge tearing, surface scratches and local thickness fluctuations, and make the tension distribution in the continuous hot rolling process smoother.

[0141] In summary, this application establishes a decreasing tension control relationship between multiple hot rolling processes, so that the tension parameters on the unwinding and rewinding sides are adapted to the gradually thinning process of the tin strip. This ensures the stability of continuous conveying while improving the forming consistency, surface flatness, and subsequent rewinding quality of the ultra-thin tin foil.

[0142] Ultra-thin strips are extremely sensitive to stress conditions during continuous conveying and rolling. Uneven distribution of transverse or longitudinal stress can easily lead to problems such as central arching, edge fluctuations, local wrinkles, and even breakage. These defects further cause surface unevenness, increased thickness fluctuations, poor subsequent winding, and reduced finished product utilization. Especially as tin strip specifications continue to evolve towards thinner dimensions, traditional processes often struggle to balance thinning capability, continuous stability, and surface quality. It is difficult to efficiently achieve the target thickness while ensuring batch consistency of ultra-thin tin foil, thus becoming a significant factor restricting the large-scale application of related products.

[0143] Furthermore, in this application, as one feasible implementation, the method for preparing tin foil further includes a wrinkle removal step, which specifically includes:

[0144] After the hot rolling step is terminated and before the coiling tension adjustment step, the surface of the workpiece is inspected to identify the location of the bulges.

[0145] Along the direction of workpiece movement, cut off the portions on both sides of the raised position of the workpiece to obtain the final workpiece.

[0146] In this application, the wrinkle removal step refers to a post-processing step that identifies and removes any local bulges, wrinkles, or wave deformations that may exist on the surface of the workpiece after the last hot rolling and before the workpiece enters the winding tension adjustment step.

[0147] The purpose of the wrinkle removal step is to locally remove the defective area so that the remaining section forms a final workpiece that meets the flatness requirements.

[0148] This wrinkle removal step is usually set between the hot rolling and winding tension adjustment steps, and can be completed collaboratively by the detection unit, positioning unit, and cutting unit.

[0149] The detection unit is used to scan the continuous surface of the workpiece, and the positioning unit is used to determine the position of the bulge based on the scanning results.

[0150] The cutting unit then cuts off both sides of the raised position along the workpiece movement direction according to the positioning result.

[0151] The detection unit is arranged coaxially or adjacent to the conveying mechanism so that online identification can be completed while the workpiece is being continuously conveyed.

[0152] The cutting unit is preferably located downstream of the detection unit and is electrically or signal-connected to the control system so as to synchronously execute the cutting action according to the detection result.

[0153] In one possible embodiment, the detection unit may employ an industrial camera in conjunction with line laser scanning to obtain the height profile of the workpiece surface and identify the location of bulges.

[0154] In another possible embodiment, the detection unit may employ a displacement sensor array to perform multi-point measurements in the width direction of the workpiece.

[0155] In another possible embodiment, the detection unit may employ a mechanical contact type detection component linked with a servo actuator to achieve defect location.

[0156] In one possible embodiment, the cutting unit may include a reciprocating cutter.

[0157] In another possible embodiment, the cutting unit may include a rotary blade wheel.

[0158] In yet another possible embodiment, the cutting unit may include a laser cutting head.

[0159] The cutting positions are arranged on both sides of the raised area along the workpiece movement direction. The cutting spacing can be determined according to the size of the raised area and the surrounding stress distribution, and is usually a safe cutting distance in the range of millimeters to tens of millimeters to reduce the diffusion of residual stress to the retained area. For example, 10-30mm.

[0160] The cutting depth should at least penetrate the tin strip body without interfering with the downstream conveying mechanism, and the cut edge should be as flat as possible to facilitate subsequent winding or reprocessing.

[0161] Furthermore, the detection unit, cutting unit, and conveying unit can be linked in a closed loop through a controller. The controller calculates the start and end boundaries of the bulge based on the surface contour data and outputs a cutting command to ensure that the cutting timing matches the workpiece conveying speed.

[0162] During the operation, the tin strip after the last hot rolling continues to move forward under the drive of the conveying mechanism. The detection unit continuously scans its surface and identifies local raised areas. Based on the detection results, the control system determines the start and end range of the raised position in the length direction of the workpiece and the safe cut-off interval on both sides. Then, the cutting unit is driven to cut on both sides of the raised position, removing the middle section containing defects and retaining only the relatively flat effective sections on both sides as the final workpiece.

[0163] Since this wrinkle removal step is set before the winding tension adjustment step, it can eliminate wrinkles and arching defects before the workpiece enters the winding state, reducing the risk of defects being compacted or solidified under the action of winding tension, thereby reducing the risk of subsequent poor winding shape, local stress concentration and surface undulation of the finished product.

[0164] Based on the above analysis, it can be seen that the method for preparing tin foil can improve the surface flatness and winding stability of the final tin foil workpiece without significantly increasing the overall process complexity, and helps to improve the adaptability of subsequent slitting, laminating and mounting processes.

[0165] As one feasible implementation method, the method for preparing tin foil further includes a lubrication step, which specifically includes:

[0166] After each unwinding tension adjustment step and before each hot rolling, a lubricant is sprayed onto the surface of the workpiece.

[0167] The lubrication step in this application is used to form a preset lubricating layer on the surface of the workpiece before the tin strip enters each hot rolling pass, so as to reduce the contact friction between the workpiece and the hot rolling roll and improve the stability of the subsequent hot pressing deformation process.

[0168] A lubricant spraying unit can be defined as a surface treatment mechanism located after the unwinding tension adjustment step and before hot rolling, which applies lubricating medium evenly to the workpiece surface through spraying, atomization deposition or roll coating.

[0169] The role of this lubrication unit in the overall process is to reduce the frictional resistance of the metal surface during hot rolling, reduce the probability of roller sticking, tearing, scratches and localized oxidation, and help improve the flow consistency of the workpiece under heated and pressurized conditions, thereby improving thickness uniformity and surface smoothness.

[0170] The lubrication unit is located in the middle section of the conveying channel, specifically after the unwinding tension adjusting roller 102 and in front of the hot rolling roller, and is coaxial or nearly coaxial with the conveying path of the workpiece. The nozzles or spray heads of the spraying mechanism are arranged facing the surface of the workpiece, so that the lubricant can complete continuous or intermittent coverage during the continuous movement of the workpiece.

[0171] Lubricants can be in the form of liquids, atomized droplets, colloidal films, or composite lubricating media.

[0172] In one possible embodiment, a silicone oil-based lubricant is used to form a low-friction, continuous liquid film.

[0173] In another possible embodiment, a composite lubricant of silicone oil and graphene nanoparticles is used to balance lubrication and friction reduction with anti-wear stability.

[0174] In another possible embodiment, a sprayable lubricant containing trace amounts of wax or polymeric lubricant additives is used to improve the adhesion and retention of the lubricated layer before hot rolling.

[0175] As one feasible implementation, the method for preparing tin foil further includes an auxiliary conveying step, which includes:

[0176] After the unwinding step, the workpiece is conveyed to the unwinding tension adjusting roller 102 via the first auxiliary roller 101;

[0177] The workpiece, after being adjusted by the unwinding tension adjusting roller 102, is conveyed to the hot rolling roll via the second auxiliary roller 103;

[0178] After hot rolling, the workpiece is conveyed to the winding tension adjusting roller 108 via the third auxiliary roller 107;

[0179] The workpiece, after being adjusted by the winding tension adjusting roller 108, is conveyed to the winding mechanism 110 via the fourth auxiliary roller 109.

[0180] In this application, the first auxiliary roller 101, the second auxiliary roller 103, the third auxiliary roller 107 and the fourth auxiliary roller 109 are all guiding and supporting components in the strip conveying path. Their function is to continuously transfer the tin strip between the functional units of unwinding, tension adjustment, hot rolling and rewinding, so as to maintain the stability of the workpiece during the roll-to-roll processing.

[0181] The first auxiliary roller 101 is disposed between the unwinding mechanism 100 and the unwinding tension adjusting roller 102, and is used to initially guide the workpiece after it is released by the unwinding mechanism 100, so that the workpiece enters the unwinding tension adjusting roller 102 at a predetermined height and direction.

[0182] The second auxiliary roller 103 is disposed between the unwinding tension adjusting roller 102 and the hot rolling roller, and is used to smoothly feed the tension-corrected workpiece into the hot rolling area and reduce the posture deviation of the workpiece before entering the hot rolling roller.

[0183] The third auxiliary roller 107 is located between the hot rolling roller and the winding tension adjusting roller 108. It is used to transition and receive the hot-rolled workpiece, reducing fluctuations or wrinkles caused by sudden changes in force after the workpiece leaves the hot rolling area.

[0184] The fourth auxiliary roller 109 is located between the winding tension adjusting roller 108 and the winding mechanism 110. It is used to stably guide the tension-adjusted workpiece into the winding mechanism 110 and ensure the neat stacking of the strip during the winding process.

[0185] During the operation, after the workpiece is released by the unwinding mechanism 100, it first passes through the first auxiliary roller 101 and enters the unwinding tension regulating roller 102. After the unwinding tension regulating roller 102 applies a preset tension to the workpiece, the workpiece is then smoothly fed into the hot rolling roll for thinning processing via the second auxiliary roller 103.

[0186] After hot rolling, the workpiece is received by the third auxiliary roller 107 and conveyed to the winding tension adjusting roller 108. After the winding tension adjusting roller 108 corrects the tension state of the workpiece again, the workpiece enters the winding mechanism 110 via the fourth auxiliary roller 109 to complete the winding.

[0187] Since each auxiliary roller undertakes the transition, support and guidance functions between different work stations, the workpiece can maintain a relatively stable belt centerline and tension distribution during continuous conveying, reducing deviation, twisting, scratches or local wrinkles caused by sudden changes in the path when switching work stations. This helps to maintain the uniformity of stress during hot rolling and the neatness of layer winding during coiling, thereby improving the continuity, stability and surface quality of the tin strip to tin foil conversion process.

[0188] This auxiliary conveying step provides a reliable material transfer basis for multiple hot rolling processes, improving the conveying accuracy, process continuity, and batch consistency in the ultra-thin tin foil manufacturing process.

[0189] It is understandable that there are two second auxiliary rollers 103. There can also be two third auxiliary rollers 107.

[0190] As one feasible implementation method, performing at least three hot rolling cycles on the initial workpiece to obtain the final workpiece specifically includes:

[0191] After the initial state workpiece is unwound by the unwinding mechanism 100, it is sent to the unwinding tension adjusting roller 102 for tension adjustment to obtain the intermediate state workpiece a1; wherein, the tension of the unwinding tension adjusting roller 102 is F1;

[0192] Intermediate workpiece a1 is hot-rolled to obtain intermediate workpiece a2; the hot rolling pressure is M1.

[0193] The intermediate workpiece a2 is wound into the winding mechanism 110 after the tension is adjusted by the winding tension adjusting roller 108 to obtain the intermediate workpiece a; wherein, the tension of the winding tension adjusting roller 108 is F2;

[0194] After the intermediate workpiece a is unwound by the unwinding mechanism 100, it is sent to the unwinding tension adjusting roller 102 for tension adjustment to obtain the intermediate workpiece b1; wherein, the tension of the unwinding tension adjusting roller 102 is F3;

[0195] Intermediate workpiece b1 is hot-rolled to obtain intermediate workpiece b2; the hot rolling pressure is M2.

[0196] The intermediate workpiece b2 is wound into the winding mechanism 110 after the tension is adjusted by the winding tension adjusting roller 108 to obtain the intermediate workpiece b; wherein, the tension of the winding tension adjusting roller 108 is F4;

[0197] After the intermediate workpiece b is unwound by the unwinding mechanism 100, it is sent to the unwinding tension adjusting roller 102 for tension adjustment to obtain the intermediate workpiece c1; wherein, the tension of the unwinding tension adjusting roller 102 is F5;

[0198] Intermediate workpiece c1 is hot-rolled to obtain intermediate workpiece c2; the hot rolling pressure is M3.

[0199] The intermediate workpiece c2 is wound into the winding mechanism 110 after the tension is adjusted by the winding tension adjusting roller 108 to obtain the final workpiece; wherein, the tension of the winding tension adjusting roller 108 is F6.

[0200] During the operation, the initial state tin strip is first unwound by the unwinding mechanism 100 and enters the unwinding tension adjusting roller 102 along the feeding path. After the tension is set under the action of F1, it forms an intermediate workpiece a1. Then, under the hot rolling pressure M1, it passes through the hot rolling zone to complete the first thinning and obtain the intermediate workpiece a2. Subsequently, it is wound and shaped by the winding tension adjusting roller 108 with F2 and then wound back to the winding mechanism 110 to form the intermediate workpiece a.

[0201] When intermediate workpiece a is unwound again, the workpiece sequentially undergoes a second unwinding tension adjustment, a second hot rolling, and a second winding tension adjustment, correspondingly forming intermediate workpieces b1, b2, and b.

[0202] In the third cycle, the final tension setting, the third hot rolling thinning, and the coiling are completed using F5, M3, and F6, thus obtaining the final workpiece.

[0203] Because the strip is controlled in a coordinated manner by tension regulating rollers on the unwinding and winding sides at each stage, the tin strip is kept in a sufficiently straight and stable feeding state before entering the hot rolling rolls, and local relaxation and fluctuations are eliminated in time after leaving the hot rolling zone. Therefore, the risk of deviation, wrinkling and edge warping of intermediate workpieces during continuous transfer can be reduced, and the plastic deformation generated by the three hot rolling processes can be made more uniform and controllable.

[0204] Based on the above process, it can be seen that the method for preparing tin foil takes into account both tension stability and winding consistency, thereby improving the thickness uniformity, surface flatness and continuous processing stability of the final tin foil, and reducing problems such as strip breakage, wrinkles and poor winding caused by tension imbalance.

[0205] Hot rolling rolls are used to hot roll initial state workpiece, intermediate state workpiece a, and intermediate state workpiece b; the roll speed ratio of hot rolling rolls is A, and A satisfies: 0.8≤A≤1.

[0206] Specifically, controlling the roll speed ratio A within the near-synchronous or weak differential speed range of 0.8-1 effectively reduces the relative slippage between the roll and the tin strip, suppresses surface scratches and marks, and ensures the surface smoothness of the tin foil.

[0207] The moving speed of the workpiece is B, and B satisfies: 1m / min≤B≤5m / min;

[0208] By limiting B to 1m / min≤B≤5m / min, a stable production cycle is maintained, and sufficient recrystallization time is provided for each pass of hot deformation, thus avoiding the accumulation of work hardening due to excessive speed.

[0209] M1 satisfies: 7.5T≤M1≤8.5T;

[0210] M2 satisfies: 6.5T≤M2≤7.5T;

[0211] M3 satisfies: 12.5T ≤ M3 ≤ 13.5T;

[0212] M1, M2, and M3 correspond to the loading pressures in the three hot rolling processes, respectively. The graded configuration of M1, M2, and M3 corresponds to the deformation requirements of the first large thinning rate rolling (96%), the second medium thinning rate rough rolling (50%), and the third finish rolling (50%), respectively. This achieves a reasonable distribution of pressure from extreme thinning to thickness fine adjustment, ensuring overall thinning efficiency while avoiding strip breakage or uneven microstructure caused by excessive pressure in a single pass.

[0213] F1 satisfies: 57N≤F1≤63N;

[0214] F2 satisfies: 17N≤F2≤23N;

[0215] F3 satisfies: 17N≤F3≤23N;

[0216] F4 satisfies: 6N≤F4≤10N;

[0217] F5 satisfies: 6N≤F5≤10N;

[0218] F6 satisfies: 4N≤F6≤6N.

[0219] F1, F2, F3, F4, F5, and F6 correspond to six tension control nodes. In terms of tension control, nodes F1-F6 employ a decreasing tension gradient from the unwinding end (57-63N) to the rewinding end (4-6N). F1 provides sufficient unwinding traction to stabilize the material supply. F2 and F3 maintain moderate tension at the rolling inlet side to prevent stacking and wrinkling. F4, F5, and F6 gradually reduce tension at the exit and rewinding ends to prevent deformation or breakage of the ultra-thin tin foil due to excessive stretching. This decreasing tension adjustment is particularly suitable for drastic changes in thickness, from 1mm to 10μm, ensuring smooth operation and tight winding of the thin strip at each stage.

[0220] The method for preparing tin foil provided in this application includes the following process: one-time rolling - rough rolling - finish rolling - finished product. The specific method is as follows:

[0221] One rolling process:

[0222] A 1mm thick tin strip (tin content: 99.99%) is unwound by the unwinding mechanism 100, and then passes sequentially through the first auxiliary roller 101, the unwinding tension adjusting roller 102 (preferred tension range: 60±3N), and the second auxiliary roller 103. A silicone oil spraying mechanism 104 then evenly sprays silicone oil onto the surface of the tin strip. It subsequently enters the roll press 105 for roll pressing (preferred pressure range: 8±0.5T; preferred roll pressing temperature range: 40±5℃). After roll pressing, a 40±3.8μm thick tin strip is obtained. This strip then passes sequentially through the third auxiliary roller 107, the winding tension adjusting roller 108 (preferred tension range: 20±3N), and the fourth auxiliary roller 109, before being wound into a coil by the winding mechanism 110.

[0223] Rough rolling:

[0224] A 40μm solder strip roll is unwound by the unwinding mechanism 100, and then passes sequentially through the first auxiliary roller 101, the unwinding tension adjusting roller 102 (preferred tension range: 20±3N), and the second auxiliary roller 103. A silicone oil spraying mechanism 104 then evenly sprays silicone oil onto the surface of the solder strip. It subsequently enters the roll press 105 for roll pressing (preferred pressure range: 7±0.5T; preferred roll pressing temperature range: 40±5℃). After roll pressing, a solder strip with a thickness of 20±2.0μm is obtained. This strip then passes sequentially through the third auxiliary roller 107, the winding tension adjusting roller 108 (preferred tension range: 8±2N), and the fourth auxiliary roller 109, before being wound into a roll by the winding mechanism 110.

[0225] Finishing rolling:

[0226] A 20μm tin strip roll is unwound by the unwinding mechanism 100, and then passes sequentially through the first auxiliary roller 101, the unwinding tension adjusting roller 102 (preferred tension range: 8±2N), and the second auxiliary roller 103. A silicone oil spraying mechanism 104 then evenly sprays silicone oil onto the surface of the tin strip. It subsequently enters the roll press 105 for roll pressing (preferred pressure range: 13±0.5T; preferred roll pressing temperature range: 40±5℃). After roll pressing, a tin strip with a thickness of 10±2.4μm is obtained. This strip then passes sequentially through the wrinkle removal mechanism 106, the third auxiliary roller 107, the winding tension adjusting roller 108 (preferred tension range: 5±1N), and the fourth auxiliary roller 109, before being wound into a roll by the winding mechanism 110.

[0227] In tin strip rolling tests, it was found that, under the same conditions, the reduction rate of hot rolling (i.e., hot pressing) is greater than that of cold rolling. For example, during cold pressing, the maximum thickness that a 1mm thick tin strip can be reduced to is 120μm, while using hot pressing at 40℃ (with all other conditions the same), the maximum thickness that a 1mm thick tin strip can be reduced to is 40μm, increasing the reduction rate from 88% to 96%. Furthermore, related technologies typically require annealing the rolled foil to eliminate work hardening before further thinning. In contrast, the hot-rolled tin strip in this application can be immediately subjected to a second hot rolling process without heat treatment, reducing the process steps, increasing production efficiency, and reducing production costs.

[0228] In related technologies, when thinning 20μm thick tin strip, an arching phenomenon occurs in the middle of the rolled tin strip. These arches form wrinkles when passing through the transition roller, resulting in poor surface quality of the foil. In related technologies, the working principle of the traditional wrinkle removal mechanism 106 is to clamp the foil and apply tension to both sides to eliminate wrinkles. However, when the tin strip thickness reaches 20μm, the thinness causes the tin strip to tear easily with slight tension, making effective wrinkle removal impossible. To address the above situation, this application adds a wrinkle removal mechanism 106 between the roll press 105 and the third auxiliary roller 107. Its structure consists of two liftable cutters. The principle is to cut the rolled tin strip 10-30mm away from the raised position along the conveyor belt direction to release the stress in the middle of the rolled tin strip, reduce the arching phenomenon in the middle of the tin strip, and thus prevent wrinkles from occurring when it passes through the third auxiliary roller 107.

[0229] Furthermore, the effect of sprayed silicone oil on roll forming thickness:

[0230] A 120μm thick tin strip was pressed thinner under the same conditions, with the amount of silicone oil gradually increased. Each test was randomly repeated three times, and the silicone oil on the surface of the hot rolling roll was cleaned before each test. Test data are shown in Tables 1 and 2. Figure 4 As shown, the P-value < 0.05 indicates that at least one set of parameters has a significant impact on the calendering thickness. Furthermore, the box plot clearly shows that the calendering thickness changes significantly with 0.1 mL of silicone oil compared to 0 mL (no silicone oil); however, there is no significant change in calendering thickness between 0.5 mL and 0.1 mL of silicone oil. Therefore, the application of silicone oil has a significant impact on the calendering thickness, while the amount of silicone oil has no significant effect.

[0231] Table 1

[0232]

[0233] Table 2

[0234]

[0235] The effect of roll speed ratio on roll thickness:

[0236] A 120μm thick tin strip was pressed thin under the same conditions, with the roller speed ratio gradually decreasing from 1. Each test was randomly repeated three times. Experimental data are shown in Tables 3 and 4. Figure 5 As shown, the P value < 0.05 indicates that the differential speed ratio has a significant impact on the rolling thickness. Differential rolling can reduce the rolling thickness compared to the same speed rolling, and the magnitude of the differential speed ratio is inversely proportional to the rolling thickness.

[0237] Table 3

[0238]

[0239] Table 4

[0240]

[0241] The effect of belt speed on roll thickness:

[0242] A 120μm thick tin strip was thinned under the same conditions, with the tape feeding speed gradually increased from 1m / min. Each test was randomly repeated three times. The experimental data are shown in Tables 5 and 6. Figure 6 As shown, the P-value > 0.05 indicates that the belt speed has no significant effect on the calendering thickness. A belt speed of 1-5 m / min has no effect on the calendering thickness, and changing the belt speed during the calendering process has no impact on the stability of the calendering thickness.

[0243] Table 5

[0244]

[0245] Table 6

[0246]

[0247] The effect of roll forming temperature on roll forming thickness:

[0248] A 120μm thick tin strip was pressed thin under the same conditions, with the rolling temperature gradually increasing. Each test was randomly repeated three times. Experimental data are shown in Tables 7 and 8. Figure 7 As shown, the P-value < 0.05 indicates that the rolling temperature has a significant impact on the rolled thickness. The rolling temperature is inversely proportional to the rolled thickness, and the thickness reduction in the hot-pressing process is more significant compared to the cold-pressing process. Furthermore, experiments have shown that the most suitable temperature for hot-pressing tin strip is 40℃ (above 40℃, tin strip is prone to breakage).

[0249] Table 7

[0250]

[0251] Table 8

[0252]

[0253] The effect of tension on roll thickness

[0254] A 120μm thick tin strip was compressed under the same conditions, with the winding / unwinding tension gradually increased. Each test was randomly repeated three times. The experimental data are shown in Tables 9 and 10. Figure 8 As shown, the P value > 0.05 indicates that the tension has no significant effect on the rolling thickness.

[0255] Table 9

[0256]

[0257] Table 10

[0258]

[0259] The maximum deviation refers to the maximum absolute value of the difference between the measured thickness value and the average thickness value of the group in a single experiment.

[0260] The coefficient of variation (Cv), also known as the coefficient of dispersion, is calculated as (standard deviation / mean) × 100%. It is an indicator of the relative magnitude of fluctuation, eliminating the influence of the mean itself.

[0261] Degrees of freedom refer to the number of independent data points that can vary freely in the data; simply put, it is the number of valid samples that can be used to estimate parameters.

[0262] The Adjusted Sum of Squares (SS), also known as the sum of squares of deviations, is the sum of squares of the deviations of data from the mean and is used to measure the magnitude of total variation.

[0263] Adj MS (Adjusted Mean Square) is Adj SS / degrees of freedom, which is equivalent to "the average amount of variation contributed by each degree of freedom", and is essentially variance.

[0264] The F-statistic formula is factor Adj MS / error Adj MS, which is the ratio of "variation caused by factors" to "variation caused by random errors".

[0265] The P-value is the probability of the current F-value (or even a higher value) occurring under the assumption that "this factor has no effect on the outcome".

[0266] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for preparing tin foil, characterized in that, A method for preparing tin foil includes: The initial workpiece is hot-rolled at least three times to obtain the final workpiece. The initial state workpiece is a solder strip.

2. The method for preparing tin foil according to claim 1, characterized in that, The hot rolling temperature is T, and T satisfies: 35℃≤T≤45℃.

3. The method for preparing tin foil according to claim 1, characterized in that, The at least three hot rolling steps include an initial hot rolling step, an intermediate hot rolling step, and a final hot rolling step, wherein the intermediate hot rolling step is performed multiple times. The hot rolling pressure in the initial hot rolling step is greater than the hot rolling pressure in the intermediate hot rolling step. The hot rolling pressure in the terminating hot rolling step is greater than the hot rolling pressure in the initial hot rolling step.

4. The method for preparing tin foil according to claim 3, characterized in that, Each hot rolling process includes an uncoiling step and an uncoiling tension adjustment step before each hot rolling process, and a coiling tension adjustment step and a coiling step after each hot rolling process. In the unwinding tension adjustment step, the tension of the unwinding tension adjustment roller (102) is greater than the tension of the winding tension adjustment roller (108) in the winding tension adjustment step.

5. The method for preparing tin foil according to claim 4, characterized in that, The tension of the unwinding tension adjusting roller (102) in the unwinding tension adjusting step before the previous hot rolling is greater than the tension of the unwinding tension adjusting roller (102) in the unwinding tension adjusting step before the next hot rolling. And / or, the tension of the winding tension adjusting roller (108) in the winding tension adjusting step after the previous hot rolling is greater than the tension of the winding tension adjusting roller (108) in the winding tension adjusting step after the subsequent hot rolling.

6. The method for preparing tin foil according to claim 4, characterized in that, It also includes a wrinkle removal step, which specifically includes: After the hot rolling termination step and before the coiling tension adjustment step, the surface of the workpiece is inspected to identify the location of any protrusions. Along the moving direction of the workpiece, the portions on both sides of the raised position of the workpiece are cut off to obtain the final workpiece.

7. The method for preparing tin foil according to claim 4, characterized in that, It also includes a lubrication step, which specifically includes: After each unwinding tension adjustment step and before each hot rolling, a lubricant is sprayed onto the surface of the workpiece.

8. The method for preparing tin foil according to claim 6, characterized in that, It also includes an auxiliary conveying step, which includes: After the unwinding step, the workpiece is conveyed to the unwinding tension adjusting roller (102) via the first auxiliary roller (101). The workpiece, after being adjusted by the unwinding tension adjusting roller (102), is conveyed to the hot rolling roll via the second auxiliary roller (103); After the hot rolling, the workpiece is conveyed to the winding tension adjusting roller (108) via the third auxiliary roller (107). The workpiece adjusted by the winding tension adjusting roller (108) is conveyed to the winding mechanism (110) via the fourth auxiliary roller (109).

9. The method for preparing tin foil according to claim 4, characterized in that, The initial workpiece is subjected to at least three hot rolling processes to obtain the final workpiece, specifically including: After the initial state workpiece is unwound by the unwinding mechanism (100), it is sent to the unwinding tension adjusting roller (102) for tension adjustment to obtain the intermediate state workpiece a1; wherein, the tension of the unwinding tension adjusting roller (102) is F1; The intermediate workpiece a1 is hot-rolled to obtain the intermediate workpiece a2; the hot-rolling pressure is M1. The intermediate workpiece a2 is wound into the winding mechanism (110) after the tension is adjusted by the winding tension adjusting roller (108) to obtain the intermediate workpiece a; wherein, the tension of the winding tension adjusting roller (108) is F2; After the intermediate workpiece a is unwound by the unwinding mechanism (100), it is sent to the unwinding tension adjusting roller (102) for tension adjustment to obtain the intermediate workpiece b1; wherein, the tension of the unwinding tension adjusting roller (102) is F3; The intermediate workpiece b1 is hot-rolled to obtain the intermediate workpiece b2; the hot-rolling pressure is M2. The intermediate workpiece b2 is wound into the winding mechanism (110) after the tension is adjusted by the winding tension adjusting roller (108) to obtain the intermediate workpiece b; wherein, the tension of the winding tension adjusting roller (108) is F4; After the intermediate workpiece b is unwound by the unwinding mechanism (100), it is sent to the unwinding tension adjusting roller (102) for tension adjustment to obtain the intermediate workpiece c1; wherein, the tension of the unwinding tension adjusting roller (102) is F5; The intermediate workpiece c1 is hot-rolled to obtain the intermediate workpiece c2; the hot-rolling pressure is M3. The intermediate workpiece c2 is wound into the winding mechanism (110) after the tension is adjusted by the winding tension adjusting roller (108) to obtain the final workpiece; wherein, the tension of the winding tension adjusting roller (108) is F6.

10. The method for preparing tin foil according to claim 9, characterized in that, At least one of the following constraints must be met: The hot rolling roll is used to hot roll the initial state workpiece, the intermediate state workpiece a, and the intermediate state workpiece b; the roll speed ratio of the hot rolling roll is A, and A satisfies: 0.8≤A≤1; The moving speed of the workpiece is B, and B satisfies: 1m / min≤B≤5m / min; The condition M1 satisfies: 7.5T ≤ M1 ≤ 8.5T; The condition M2 satisfies: 6.5T ≤ M2 ≤ 7.5T; The condition M3 satisfies: 12.5T ≤ M3 ≤ 13.5T; The F1 satisfies: 57N≤F1≤63N; The F2 satisfies: 17N≤F2≤23N; The F3 satisfies: 17N≤F3≤23N; The F4 satisfies: 6N≤F4≤10N; The condition F5 satisfies: 6N≤F5≤10N; The condition F6 satisfies: 4N≤F6≤6N.

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