A multi-station processing device and method for stainless steel kitchenware

Abstract

This invention discloses a multi-station processing method and apparatus for stainless steel kitchenware, solving the problems of difficult-to-control springback and large taper deviation caused by changes in the mechanical properties of porous plates in the traditional processing of conical porous stainless steel steam grates, as well as the reliance on operator experience and high production costs. The processing method includes four sequential steps: pretreatment and process parameter determination, multi-stage progressive shaping, online detection and compensation, and finishing calibration. Through the linkage and matching of hole group parameters and process parameters, dynamic allocation coefficient adjustment, online springback compensation, and accurate finishing, efficient and high-precision shaping of porous stainless steel billets is achieved. The processing apparatus is set up accordingly to achieve automated connection and accurate control of each process. This invention eliminates the need for multiple mold trials and repairs, shortens the production cycle, reduces production costs, improves the taper accuracy and stability of the product, and is suitable for the quality requirements of high-end stainless steel kitchenware. It can be applied to the large-scale production of conical porous stainless steel steam grates.

Description

Technical Field

[0001] This invention relates to the field of hardware processing technology, specifically to a multi-station processing device and method for stainless steel kitchenware. Background Technology

[0002] Porous stainless steel steaming racks are core kitchen appliances used in both household and catering settings. Thanks to the excellent corrosion resistance and high-temperature resistance of stainless steel, as well as the unique air permeability and drainage advantages of its porous structure, they are widely used in various cooking containers such as steamers and soup pots, serving as a key component for achieving steaming cooking functions. Among various types of porous stainless steel steaming racks, the conical structure porous stainless steel steaming rack (see appendix) is particularly popular. Figure 1 Because it can fit the concave shape of most pots, facilitates the even flow of steam, and effectively avoids water residue during steaming, it has become the mainstream product form in the current market.

[0003] Currently, the processing technology for conical porous stainless steel steam grates generally adopts the process of "flat plate punching → conical surface shaping". However, in actual large-scale production, this conventional processing flow has a shortcoming: before the conical surface shaping process, the sheet metal has already undergone dense punching. The densely distributed hole clusters are equivalent to introducing a large number of periodic structural weakening zones inside the sheet metal, which in turn changes the overall mechanical properties of the sheet metal, such as the equivalent elastic modulus, yield strength, and plastic flow characteristics, thus causing production and product quality problems.

[0004] Specifically, the aforementioned changes in mechanical properties mainly lead to two major problems: First, traditional springback calculation formulas are all derived from non-porous homogeneous flat plate materials, which cannot be adapted to the special mechanical properties of porous plates after punching. This makes it impossible to accurately calculate and predict the springback amount of the plate during the tapered surface shaping process after punching, making it difficult to control the taper accuracy. Second, in the process of mass production, affected by factors such as batch fluctuations of raw materials, wear and tear of molds after long-term use, and changes in stamping pressure, products in the same batch are prone to taper deviation defects, affecting the product qualification rate.

[0005] To address the aforementioned issues, most industries currently rely on operators' past experience for production, requiring multiple trial molds and repairs to match the springback of the sheet metal. This not only leads to long mold development cycles and significantly increased production costs, but also makes it difficult to stably control the taper precision of products, failing to meet the quality standards of high-end food kitchenware and thus hindering the development of the stainless steel kitchenware industry. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-station processing device and method for stainless steel kitchenware, which does not have at least one of the disadvantages mentioned above.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-station processing method for stainless steel kitchenware, comprising the following steps: S1: Pre-processing, punching holes in the blank to form a hole group structure, and simultaneously collecting hole group distribution parameters; Based on the pore group distribution parameters, determine the total number of subsequent multi-stage progressive shaping stages N and the allocation coefficient β; Multi-stage progressive shaping: This process uses a multi-stage progressive forming process to gradually shape the punched blank into the target cone shape. Each stage uses a die with an increasing cone angle. The forming cone angle corresponding to the die at the nth stage is ɑn=ɑ0*(n / N)^β, where ɑ0 is the target cone angle and β is the distribution coefficient. Online detection and compensation: After each shaping stage, the springback amount θn of the stamped blank is detected, and the forming cone angle of the next stage is compensated based on θn: Bn+1=(ɑn+1)+k*θn; where k is the compensation coefficient, and ɑn+1 is the theoretical mold cone angle of the (n+1)th stage in S2. S4: Finishing calibration, which performs final finishing on the workpiece after progressive shaping to eliminate residual errors.

[0008] Furthermore, in step S1, the pore group distribution parameters include pore diameter d, pore spacing p, plate thickness t, and porosity φ; in step S1.1, the pore group influencing factors A1=d / t and A2=p / d are calculated using d, p, and t, and the total order N is positively correlated with A1 and φ, and negatively correlated with A2.

[0009] Furthermore, in step S2, when N is greater than the threshold, the value of β will decrease as the total number of levels N increases, that is, the actual allocation coefficient β′=a*β0*N0 / N1, where a is the adjustment coefficient, N0 is the standard total number of levels corresponding to when A1, A2 and φ are all standard values, β0 is the standard allocation coefficient corresponding to when the total number of levels is the standard value N0, and 0.8≤β0≤1.2, β′≤1.2.

[0010] Furthermore, in the process of multi-stage progressive shaping, the allocation coefficient βn+1 corresponding to the mold of the (n+1)th stage is dynamically adjusted according to the springback trend, that is, βn+1=c*((θn-1)-θn)+βn, where θn is the measured springback amount of the nth stage. When n=1, θ0 is the target springback angle θ, β1=β′, and c is the recursive attenuation coefficient, 0.05≤c≤0.15.

[0011] Furthermore, the recursive attenuation coefficient c is positively correlated with the porosity φ, that is, the actual recursive attenuation coefficient c = b * c0 * φ1 / φ0; where c0 is the standard recursive attenuation coefficient corresponding to the porosity φ being the standard value φ0, b is the correction coefficient, and φ1 is the actual porosity of the billet.

[0012] Furthermore, in step S3, the compensation coefficient k is positively correlated with the porosity φ, that is, the actual compensation coefficient k = d * k0 * φ1 / φ0; where k0 is the standard compensation coefficient corresponding to the porosity φ being the standard value φ0, d is the correction coefficient, and φ1 is the actual porosity of the billet.

[0013] Furthermore, in step S4, the billet after multi-stage progressive shaping is heated to 150℃-300℃, and then placed in a finishing mold for heat preservation and pressure holding for 2-5 minutes.

[0014] Furthermore, in step S1, the punching process adopts a center-to-outward radial diffusion punching method, and the interval between each punching revolution is 0.4s-0.8s.

[0015] The present invention also discloses a multi-station processing device for stainless steel kitchenware for implementing the above processing method, comprising a pretreatment unit, a multi-stage progressive shaping unit, an online detection and compensation unit, a finishing and calibration unit connected in sequence, and a control system for controlling the coordinated operation of each unit; The pretreatment unit includes a punching die and a parameter acquisition module. The punching die is used to perform center-to-outward radial diffusion punching on the blank. The parameter acquisition module is used to acquire the hole distribution parameters and transmit them to the control system. The multi-level progressive shaping unit includes N progressive shaping dies connected in sequence. The cone angle of each progressive shaping die increases progressively and is electrically connected to the control system. It is used to progressively shape the blank according to the forming cone angle parameters issued by the control system. The online detection and compensation unit includes a springback detection module and a cone angle adjustment module. The springback detection module is used to detect the springback amount of the blank after each stage of shaping and transmit it to the control system. The cone angle adjustment module is used to adjust the cone angle of the next stage progressive shaping die according to the compensated cone angle calculated by the control system. The finishing calibration unit includes a heating module, a finishing mold, and a heat preservation and pressure holding module. The heating module is used to heat the progressively shaped billet to 150℃-300℃. The finishing mold is used to finish the heated billet. The heat preservation and pressure holding module is used to control the heat preservation and pressure holding time during the finishing process to be 2-5 minutes. The control system is used to receive data transmitted by the parameter acquisition module and the rebound detection module, calculate parameters such as the total number of stages N, the allocation coefficient β, and the compensated cone angle Bn+1, and control each unit to work according to the preset process.

[0016] Furthermore, the parameter acquisition module includes an aperture detector, an aperture spacing detector, a plate thickness detector, and a porosity detector, which are used to detect the aperture d, aperture spacing p, plate thickness t, and porosity φ, respectively, and transmit the detection data to the control system in real time; the springback detection module adopts a laser springback detector, and the cone angle adjustment module adopts a servo adjustment mechanism.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention addresses the problems of springback difficulty and large taper deviation caused by changes in the mechanical properties of porous plates after punching through a pre-processing parameter matching, multi-level progressive shaping, online detection compensation, and fine-tuning calibration process. It eliminates the need for operators to rely on experience for trial molding and mold repair, significantly reducing the impact of human factors on product quality. 2. By linking and matching the hole group parameters with the process parameters, the distribution coefficient is dynamically adjusted, and combined with online springback compensation at each stage, the springback amount is accurately controlled; the final finishing and calibration process eliminates residual stress and residual error, ensuring stable taper accuracy of the product, effectively improving the consistency and pass rate of products in the same batch, and meeting the quality requirements of high-end stainless steel kitchenware. 3. No need for multiple mold trials and repairs, reducing mold development and debugging time; multi-stage progressive shaping process adapts to the mechanical properties of porous sheets, reducing sheet breakage rate; fully automated control improves production efficiency, comprehensively reduces production costs, and adapts to the needs of large-scale mass production. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the billet after molding; Figure 2 This is a schematic diagram of the processing technology of the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] Example Porous stainless steel steaming racks are core kitchen appliances used in both household and catering settings. Thanks to the excellent corrosion resistance and high-temperature resistance of stainless steel, as well as the unique air permeability and drainage advantages of its porous structure, they are widely used in various cooking containers such as steamers and soup pots, serving as a key component for achieving steaming cooking functions. Among various types of porous stainless steel steaming racks, the conical structure porous stainless steel steaming rack (see appendix) is particularly popular. Figure 1 Because it can fit the concave shape of most pots, facilitates the even flow of steam, and effectively avoids water residue during steaming, it has become the mainstream product form in the current market.

[0022] Currently, the processing technology for conical porous stainless steel steam grates generally adopts the process of "flat plate punching → conical surface shaping". However, in actual large-scale production, this conventional processing flow has a shortcoming: before the conical surface shaping process, the sheet metal has already undergone dense punching. The densely distributed hole clusters are equivalent to introducing a large number of periodic structural weakening zones inside the sheet metal, which in turn changes the overall mechanical properties of the sheet metal, such as the equivalent elastic modulus, yield strength, and plastic flow characteristics, thus causing production and product quality problems.

[0023] Specifically, the aforementioned changes in mechanical properties mainly lead to two major problems: First, traditional springback calculation formulas are all derived from non-porous homogeneous flat plate materials, which cannot be adapted to the special mechanical properties of porous plates after punching. This makes it impossible to accurately calculate and predict the springback amount of the plate during the tapered surface shaping process after punching, making it difficult to control the taper accuracy. Second, in the process of mass production, affected by factors such as batch fluctuations of raw materials, wear and tear of molds after long-term use, and changes in stamping pressure, products in the same batch are prone to taper deviation defects, affecting the product qualification rate.

[0024] To address the aforementioned issues, most industries currently rely on operators' past experience for production, requiring multiple trial molds and repairs to match the springback of the sheet metal. This not only leads to long mold development cycles and significantly increased production costs, but also makes it difficult to stably control the taper precision of products, failing to meet the quality standards of high-end food kitchenware and thus hindering the development of the stainless steel kitchenware industry.

[0025] Based on the above issues, please refer to Figures 1-2 A multi-station processing method for stainless steel kitchenware includes the following steps: S1: Pre-treatment. After accurately positioning the stainless steel plate blank, dense punching is performed using a center-to-outward radial diffusion punching method to ensure uniform hole distribution and consistent hole diameter, thereby forming a hole structure that meets the product design requirements. At the same time, key parameters of the hole distribution are collected to provide data support for the accurate setting of subsequent process parameters, avoiding mismatch between the subsequent shaping process and the mechanical properties of the blank due to unknown hole parameters. The collected hole distribution parameters specifically include core indicators such as hole diameter, hole spacing, plate thickness, and porosity. Based on the pore distribution parameters collected during the preprocessing stage, the influencing factors of the pore group (pore diameter to plate thickness ratio, pore spacing to pore diameter ratio) are calculated. Combined with the influence of pore porosity on the mechanical properties of the billet, the total number of subsequent multi-stage progressive forming processes N and the initial allocation coefficient β are determined. The setting of the total number of stages N needs to be adapted to the formability of the billet, while the allocation coefficient β is used to control the deformation distribution of each forming stage, laying the foundation for the precision control of subsequent progressive forming, ensuring uniform deformation of the billet during multi-stage forming, and avoiding problems such as local cracking and excessive deformation. S2: A multi-stage progressive forming process is adopted to gradually shape the punched porous blank into the target cone shape in steps. Each stage of shaping uses a progressive shaping die, and the cone angle of each die increases progressively, gradually approaching the target cone angle, realizing the progressive deformation of the blank and dispersing the deformation stress of each step. Among them, the forming cone angle αn corresponding to the nth stage die is α0*(n / N)^β, where α0 is the target cone angle of the product design and β is the distribution coefficient determined in S1.1. The theoretical cone angle of each stage of shaping is accurately calculated through this formula to ensure that the deformation amount of each stage of shaping is controllable and the cone angle increases progressively. Online detection and compensation are used to correct springback errors during the forming process in real time, ensuring that the cone angle accuracy after each forming stage meets the preset requirements. After each progressive forming process is completed, the springback amount of the stamped blank is detected to obtain the actual springback amount θn after that stage of forming. Subsequently, based on the measured springback amount θn and the compensation coefficient k, the forming cone angle of the next progressive forming stage is accurately compensated. The compensation formula is Bn+1=αn+1+k*θn, where k is the compensation coefficient for the porosity of the hole group, and αn+1 is the theoretical die cone angle of the (n+1)th stage calculated by the theoretical formula in S2. Through this online compensation mechanism, the influence of springback on the cone accuracy can be offset in real time, avoiding error accumulation. S4: Finishing and calibration, which is the final finishing process for the workpiece that has completed all the multi-stage progressive shaping processes and has initially formed the target cone shape. By accurately controlling process parameters such as heating temperature and holding and pressure time, residual stress generated in the workpiece during the multi-stage shaping process is eliminated, minor taper deviations are corrected, the forming dimensions of the workpiece are stabilized, and residual errors are eliminated, ensuring that the taper accuracy and external dimensions of the final product meet the quality standards of high-end stainless steel kitchenware.

[0026] In one embodiment, the hole group distribution parameters include hole diameter d, hole spacing p, plate thickness t, and porosity φ. In step S1.1, the hole group influencing factors A1=d / t and A2=p / d are calculated using d, p, and t, and the total order N is negatively correlated with A1 and φ, and positively correlated with A2. Wherein, d is the diameter of a single hole in the hole group, affecting the hole wall strength and the degree of plate weakening; p is the center-to-center distance between two adjacent holes, determining the width of the material between holes and the degree of interference between holes; t is the original thickness of the stainless steel plate blank, a parameter affecting the overall stiffness of the plate; φ is the porosity, i.e., the ratio of the total area of ​​the hole group to the total area of ​​the blank, which directly reflects the density of the hole group; A1 is the hole diameter to plate thickness ratio, which can quantify the matching relationship between hole diameter and plate thickness, reflecting the bearing capacity of the hole wall; A2 is the hole spacing to hole diameter ratio, which can quantify the matching relationship between hole spacing and hole diameter, reflecting the degree of material surplus between holes. When the aperture is large and the plate thickness is thin, the aperture wall is thinner, resulting in a more significant weakening of the plate structure and a larger A1 value. This necessitates increasing the total number of stages N to distribute the deformation at each stage and prevent aperture wall breakage. Conversely, when the aperture spacing is large and the aperture is small, there is more material between the apertures, resulting in less interference and a larger A2 value. This leads to more stable local mechanical properties of the plate, allowing for a reduction in the total number of stages N and improved processing efficiency. However, when φ is large, the weakening of the plate's internal structure becomes more pronounced (dense aperture clusters reduce the number of aperture walls and decrease the material abundance between apertures), significantly reducing the plate's equivalent stiffness and aperture wall load-bearing capacity, hindering forming... Problems such as hole wall damage and board warping are prone to occur. Therefore, it is necessary to increase the total number of stages N to distribute the total deformation amount across more steps, reduce the deformation amount per stage, protect the hole wall, and avoid damage. Conversely, the smaller φ is (the sparser the hole group and the more stable the board), the greater the single-stage deformation that the board can withstand. The shaping can be completed without too many stages, which can reduce the total number of stages N and improve efficiency. In summary, the total number of stages N is positively correlated with A1 and φ, and negatively correlated with A2. The specific value of the total number of stages N can be obtained by forming a mapping table related to A1, φ, and A2 after experiments.

[0027] In the above multi-stage forming process, the allocation coefficient β is set with a fixed value, without fully considering the impact of the change in the total number of stages N on the deformation distribution of each stage. Since the total number of stages N is dynamically adjusted according to the hole group parameters (A1, A2, φ), when the actual determined total number of stages N is greater than the preset standard threshold, if the fixed allocation coefficient β is still used, it is easy to cause uneven deformation distribution. On the one hand, it may cause the deformation of the early forming stages to be too large, exceeding the bearing capacity of the porous plate (after the hole group structure is weakened), thus causing processing defects such as hole wall damage and plate warping. On the other hand, it may cause the deformation of the later forming stages to be insufficient, unable to effectively approach the target cone angle, and ultimately produce a taper deviation, affecting product accuracy and increasing the difficulty of correction in subsequent finishing processes. Based on this, in one embodiment of the present invention, if N is less than the threshold, then β = β0 is taken, where β0 is the standard allocation coefficient corresponding to the total number of stages being the standard value N0; and 0.8 ≤ β0 ≤ 1.2. This range is set based on test data of multiple sets of blanks with different specifications, which can ensure that the deformation of the early shaping stages is not excessive, effectively protect the hole wall structure of the porous plate and avoid damage, and ensure that the later shaping stages have sufficient deformation to achieve accurate taper approximation and fine-tuning correction. When N is greater than the threshold, the value of β will decrease as the total number of stages N increases. That is, the actual distribution coefficient β′=a*β0*N0 / N1, where a is an adjustment coefficient, mainly used to fine-tune according to the differences in actual production scenarios, adapt to the performance differences of different specifications of blank materials (such as 304 and 316 stainless steel) and different precision levels of stamping equipment. Its value range is usually set to 0.9-1.1 after experimental verification. Therefore, when the actual total number of stages N increases, the actual distribution coefficient β′ decreases synchronously. Its essence is to evenly distribute the fixed total deformation amount (the total deformation amount from the flat blank to the target cone shape) to more shaping stages, ensuring that the deformation amount of each shaping stage is within a reasonable range. If N increases while β′ remains constant, the deformation in the early shaping stages will surge, exceeding the bearing capacity of the porous plate (after structural weakening), leading to cracking of the pore walls and deformation of the plate. Simultaneously, insufficient deformation in later shaping stages will fail to effectively correct the earlier deformation deviations, ultimately resulting in loss of taper accuracy. By using the calculation logic of a*β0*N0 / N, a smaller distribution coefficient can be achieved with more shaping stages, allowing the deformation of each stage to be gradually adjusted as the number of stages increases, avoiding deformation accumulation and ensuring a smooth and controllable progressive shaping process. Furthermore, the limitation of β0's value range (0.8 ≤ β0 ≤ 1.2, β′ ≤ 1.2) further ensures the rationality of the formula application: if β′ is too small, the deformation amount of each shaping stage will be too uniform, and the subsequent shaping stages will not be able to form an effective finishing correction margin, making it difficult to correct small taper deviations; if β′ is too large, the deformation amount of the early shaping stages will surge, damaging the pore structure of the porous plate and causing processing defects. This value range can take into account both deformation uniformity and plate protection, thereby ensuring the feasibility and stability of the process. Therefore, this invention further optimizes the deformation control logic of multi-stage progressive shaping, enabling the allocation coefficient to be dynamically adapted according to the actual total number of stages, effectively avoiding the defects of excessive deformation in the early stage and insufficient deformation in the later stage, improving the stability of taper accuracy, reducing the processing breakage rate of porous plates, and laying the foundation for the accurate implementation of subsequent online detection and compensation processes, further promoting the standardization and high precision of porous stainless steel kitchenware processing technology.

[0028] In the aforementioned multi-stage progressive forming process, the distribution coefficient β has the same value in each stage of the forming process, which does not fully consider the characteristics of the porous stainless steel billet during the forming process, namely the dynamic change of springback. Specifically, after each stage of forming, the porous sheet material will undergo a certain degree of work hardening, and its equivalent elastic modulus, yield strength and other mechanical properties will gradually change, resulting in a continuous decreasing trend of springback after each stage of forming. The distribution coefficient β with the same value can only distribute the deformation amount of each stage according to the preset fixed ratio, and cannot be adjusted in real time according to the actual springback situation. This easily leads to the continuous accumulation of springback error, and the later forming cannot effectively offset the springback deviation of the early stage, making it difficult to effectively guarantee the taper accuracy.

[0029] Based on this, in one embodiment of the present invention, that is, in the process of multi-level progressive shaping, the allocation coefficient βn+1 corresponding to the mold of the (n+1)th level is dynamically adjusted according to the springback change trend, βn+1=c*((θn-1)-θn)+βn, θn is the measured springback amount of the nth level, when n=1, θ0 is the target springback angle θ, β1=β′, c is the recursive attenuation coefficient, 0.05≤c≤0.15; Wherein, βn+1 is the allocation coefficient of the (n+1)th level, which is a dynamic allocation coefficient adjusted based on the measured springback amount of the nth level. Its function is to optimize the deformation allocation ratio of the (n+1)th level in real time according to the springback deviation of the previous level, so as to ensure that the deformation amount of each level can accurately adapt to the springback state of the current plate, thereby realizing the real-time cancellation of springback error and ensuring taper accuracy. And c is the recursive attenuation coefficient, which controls the adjustment range of the allocation coefficient βn+1 and avoids taper fluctuation caused by excessive or insufficient adjustment range. Its value range is strictly limited to 0.05≤c≤0.15. This range has been verified by multiple sets of porous stainless steel billets with different specifications and different porosities, and is the optimal range that balances adjustment sensitivity and process stability. θn represents the measured springback after the (n-1)th stage of shaping, and θn represents the measured springback after the nth stage of shaping. The difference between the two directly reflects the dynamic trend of the springback. When the difference is positive and large, it indicates that the springback decreases rapidly and the work hardening of the material increases significantly. When the difference is small or close to zero, it indicates that the springback tends to stabilize and the work hardening of the material reaches saturation. βn is the allocation coefficient for the nth stage, which is the benchmark coefficient for adjusting the allocation coefficient for the (n+1)th stage. Its value is obtained by gradually adjusting the actual allocation coefficient β′ determined above, combined with the springback trend of the previous n-1 stages. n is the current shaping stage, with a value range of n≥1. When n=1, since there is no 0th stage shaping process, it is clearly defined that... The preset target springback angle θ is taken. This target springback angle θ is the optimal springback reference value preset by experiment based on standard billet and standard process parameters. β1 directly adopts the actual distribution coefficient β′ calculated above, thereby ensuring that the dynamic adjustment process has a clear initial reference, avoiding confusion of initial parameters, and ensuring the continuity and accuracy of the entire dynamic adjustment process. Therefore, this embodiment achieves the effect of adaptive distribution coefficient following the change in springback, which conforms to the material mechanical property change law during the forming process of porous sheet. From the actual processing perspective, during the forming process of porous sheet, the material will gradually undergo work hardening with each level of deformation, and the springback amount shows a continuous decreasing trend. By the difference between θn-1 and θn, the rate of decrease and trend of change of springback amount can be accurately captured: when the springback amount decreases rapidly (i.e., the difference is large), it indicates that the degree of work hardening of the material increases rapidly, and the springback ability of the sheet weakens rapidly. At this time, c multiplied by the difference will cause βn+1 to increase accordingly, thereby increasing the deformation amount distribution ratio of the (n+1)th level, achieving the effect of later finishing, and ensuring that the target cone angle can be quickly approached; when the springback amount decreases slowly (i.e., the difference is small), it indicates that the degree of work hardening of the material tends to saturate, and the springback ability tends to stabilize. At this time, the increase of βn+1 will slow down accordingly, maintaining the robustness of deformation distribution and avoiding cone fluctuations caused by excessive adjustment; Furthermore, multiple sets of experiments have shown that if the value of c is less than 0.05, the adjustment speed of the distribution coefficient βn+1 will be too slow, failing to adapt to the dynamic changes in the springback amount in a timely manner, and the springback error will continue to accumulate, making accurate compensation impossible. If the value of c is greater than 0.15, the adjustment range of the distribution coefficient βn+1 will be too large, and the fluctuation of the deformation amount at each level will be too obvious, easily causing processing defects such as taper deviation and hole wall damage, and even causing the entire shaping process to go out of control. Therefore, this embodiment solves the problems of inability to adapt to springback changes, accumulation of springback errors, and lack of standard parameter control caused by using the same allocation coefficient value in each shaping stage. Through a clearly defined dynamic adjustment formula, parameter value range, and initial condition setting, dynamic adaptive adjustment of the allocation coefficient is achieved, accurately matching the springback characteristics and material mechanical changes during the shaping process of porous plates. Simultaneously, a unified standard for parameter control is established, reducing the impact of subjective operational differences, improving the operability, repeatability, and stability of the process, effectively offsetting the accumulation of springback errors, further improving the stability of taper accuracy, reducing the processing breakage rate of porous plates, and providing strong support for the accurate implementation of subsequent online detection and compensation processes.

[0030] Porosity φ, as a parameter that directly reflects the density of pores, determines the structural integrity and mechanical stability of porous boards. The larger the φ, the denser the pore distribution, the fewer the number of pore walls inside the board, the lower the material surplus between pores, the more obvious the weakening of the overall structure of the board, and the greater the fluctuation range of mechanical properties such as equivalent elastic modulus and yield strength. This leads to irregular fluctuations in the rebound amount after each stage of shaping, resulting in decreased rebound stability. Conversely, the smaller the φ, the sparser the pore distribution, the more complete the board structure, the more stable the mechanical properties, the smaller the fluctuation range of rebound amount, and the higher the rebound stability. However, the fixed recursive attenuation coefficient c in the above scheme cannot adapt to the dynamic characteristics of rebound stability as porosity changes. Regardless of how φ changes, the same c value is used to adjust the distribution coefficient βn+1, which leads to a mismatch between the adjustment rhythm and adjustment range of βn+1 and the actual mechanical properties and rebound state of the board. When φ is large and rebound is unstable, a fixed c value that is too small will result in an excessively slow adjustment speed of the distribution coefficient, which cannot keep up with the fluctuation of rebound amount in time, and the rebound error will continue to accumulate. When φ is small and rebound is stable, a fixed c value that is too large will result in an excessive adjustment range of the distribution coefficient, causing taper fluctuations and even damaging the pore wall structure.

[0031] Based on this, in one embodiment of the present invention, it is clearly stated that the recursive attenuation coefficient c is positively correlated with the porosity φ. The calculation formula for the actual recursive attenuation coefficient c is given as c=b*c0*φ1 / φ0. Accurate adaptation of the c value is achieved through parameter linkage. Here, c is the actual recursive attenuation coefficient, used to dynamically adjust the adjustment range of the (n+1)th level distribution coefficient βn+1, determining the sensitivity of βn+1 to changes in rebound amount. This ensures the accuracy of the distribution coefficient adjustment and adapts to the main parameters of porosity changes. At the same time, the range of c is limited to 0.05≤c≤0.15 to avoid taper fluctuations or pore wall damage caused by c values ​​exceeding the range. φ is the porosity; b is the correction coefficient, used to adapt to differences in the material of different billets. For example, 304 stainless steel and 316 stainless steel have slight differences in mechanical properties, and their springback characteristics at the same porosity are also different. The correction coefficient b can accurately compensate for these material differences. Its value range has been experimentally verified and is usually set to 0.95-1.05. c0 is the standard recursive attenuation coefficient, which is the reference coefficient when the porosity φ is the preset standard value φ0. It is determined by the test data of multiple sets of standard parameter billets (A1, A2, and φ are all standard values). φ1 is the actual porosity of the billet, reflecting the main data of the density of the pore group and the mechanical properties of the current processed billet. φ0 is the standard porosity, which is the preset pore group porosity reference value, corresponding to the porosity parameter when the total standard level N0 is reached. In this embodiment, an adaptation relationship between the recursive attenuation coefficient c and the porosity φ is established, which conforms to the mechanical property law that the higher the porosity of the porous plate, the more unstable the springback. The effects of differential adaptation of porosity and dynamic matching of adjustment sensitivity are achieved. When φ1 > φ0, it indicates that the pore group of the actual blank is denser than the standard state, and the springback stability is poorer. At this time, the ratio of φ1 / φ0 is greater than 1, and the calculated c > c0. The recursive attenuation coefficient increases, and the adjustment speed of the distribution coefficient βn+1 accelerates, which can keep up with the fluctuation of the springback amount in time and effectively offset the springback error. When φ1 < φ0, it indicates that the pore group of the actual blank is sparser than the standard state, and the springback stability is better. At this time, the ratio of φ1 / φ0 is less than 1, and the calculated c < c0. The recursive attenuation coefficient decreases, and the adjustment speed of the distribution coefficient βn+1 slows down, avoiding the taper fluctuation caused by excessive adjustment, so as to achieve accurate adaptation with higher porosity and more sensitive adjustment. The correction coefficient b further improves the practicability and adaptability of the formula, can effectively compensate for the influence brought by objective factors such as blank material differences, stamping equipment precision deviation, and production environment temperature fluctuation, avoid the deviation of c value calculation caused by these objective factors, and ensure that the formula can play a stable role in different production scenarios. In addition, the calculation result still needs to satisfy 0.05 ≤ c ≤ 0.15 to constrain the formula calculation result, avoid the c value exceeding the upper limit due to too large φ1, which may lead to processing defects such as excessive adjustment amplitude of the distribution coefficient, taper fluctuation, and pore wall damage; at the same time, avoid the c value being lower than the lower limit due to too small φ1, which may lead to problems such as too slow adjustment speed of the distribution coefficient and cumulative springback error.

[0032] Therefore, this embodiment solves the problems in the existing dynamic adjustment scheme, such as inaccurate adjustment of the distribution coefficient caused by porosity change, cumulative springback error, and poor consistency of processing accuracy for blanks with different porosities. By clarifying the positive correlation between c and φ and the specific calculation formula, the dynamic adjustment strategy of the distribution coefficient is further optimized, so that the recursive attenuation coefficient c can be set differentially and accurately according to the actual porosity, ensuring that the adjustment rhythm and amplitude of the distribution coefficient βn+1 are completely matched with the actual mechanical properties and springback state of the plate. At the same time, the entire parameter control system is also improved, and the versatility and adaptability of the process are enhanced, which can meet the processing requirements of porous stainless steel blanks with different porosities and different specifications, effectively improving the stability of springback control accuracy and taper accuracy, and reducing the processing defects and product scrap rate caused by inaccurate adjustment of the distribution coefficient.

[0033] In online compensation, the compensation coefficient k is generally set to a fixed value, without fully considering the significant impact of porosity φ, a pore group parameter, on the rebound error. Porosity φ, as a core parameter that directly reflects the density of the pore group, determines the structural integrity and mechanical properties of the porous board, thus affecting the rebound amount and rebound error after each stage of shaping: the larger φ is, the denser the pore distribution, the fewer the number of pore walls inside the board, the lower the material allowance between pores, the more obvious the weakening of the overall structure of the board, and the significant decrease in mechanical properties such as equivalent elastic modulus and yield strength. It is more difficult to control the plastic deformation and elastic rebound of the material during the shaping process, which leads to a significant increase in the rebound amount θn after each stage of shaping, and the rebound error is also aggravated. Conversely, the smaller φ is, the sparser the pore distribution, the more complete the board structure, the more stable the mechanical properties, the smaller the rebound amount θn, and the relatively smaller the rebound error, making it easier to achieve error compensation. In the above scheme, regardless of how the porosity φ changes or how the springback error varies, the same fixed compensation coefficient k is used for springback compensation. This can easily lead to a mismatch between the compensation force and the actual springback error. Specifically, firstly, when φ is large and the springback error is significant, the fixed k value is too small, and the compensation amount k*θn is insufficient to offset the current springback error. This causes the unoffset springback error to accumulate in the next shaping process. Even after multiple rounds of compensation and finishing, it is difficult to completely eliminate the deviation, ultimately resulting in a significant taper deviation that affects product accuracy. Secondly, when φ is small and the springback error is small, the fixed k value is too large, and the compensation amount k*θn exceeds the actual required compensation range. This can lead to overcompensation, causing the taper angle of the next shaping process to deviate in the opposite direction. This increases the difficulty of correction in subsequent processes and may even cause processing defects such as hole wall damage and plate deformation. Based on this, in one embodiment of the present invention, addressing the problems of poor adaptability of the fixed compensation coefficient k, lack of consideration of the influence of porosity, insufficient compensation for rebound error, and lack of standard parameter control, this embodiment explicitly proposes that the compensation coefficient k is positively correlated with the porosity φ, and provides a specific calculation formula for the actual compensation coefficient k: k=d*k0*φ1 / φ0. Through parameter linkage, accurate adaptation of the compensation coefficient k is achieved, solving the inherent defects of existing online compensation schemes, further optimizing the precision control logic of online detection and compensation processes, and ensuring that rebound error is fully offset.

[0034] Among them, k is the actual compensation coefficient, which is used to calculate the specific compensation amount of the springback error after each level of shaping, and determines the compensation amplitude of the cone angle of the next-level progressive shaping die. The value of k affects the cancellation effect of the springback error and the stability of the taper accuracy. The larger the value, the stronger the compensation force, and vice versa. d is the correction coefficient, which is used to adapt to the accuracy differences of different stamping equipment and the influence of objective factors such as the production environment temperature and the degree of die wear. For stamping equipment with different accuracy levels, there are slight differences in the die positioning accuracy and pressure control accuracy, and the actual compensation effects under the same compensation coefficient are also different. The correction coefficient d can accurately compensate for this difference, and its value range is usually set to 0.9 - 1.1 through experimental verification. k0 is the standard compensation coefficient, which is the reference compensation coefficient when the porosity φ is the preset standard value φ0. It is determined by the experimental data of multiple groups of standard parameter blanks (the hole diameter d, hole pitch p, plate thickness t, and porosity φ are all preset standard values). Its value is verified through experiments to ensure that under standard working conditions, the compensation amount k0 * θn can cancel the springback error, making the compensated cone angle fit the theoretical value, and providing a reference for the calculation of the actual compensation coefficient k. φ1 is the actual porosity of the blank, that is, the actual parameters of the hole group collected by the porosity detector in the S1 pretreatment stage, which reflects the data of the density and mechanical properties of the hole group of the current processed blank. φ0 is the standard porosity, which is the preset reference value of the porosity of the hole group. θn is the measured springback amount after the nth level of shaping, which is collected in real time by the springback detection module in the online detection and compensation unit and is the data reflecting the size of the springback error of the current level of shaping; αn+1 is the theoretical die cone angle of the n + 1th level.

[0035] In this embodiment, a linkage adaptation relationship between the compensation coefficient k and the porosity φ is established, which conforms to the mechanical property law that the higher the porosity of the porous plate, the greater the springback error, and achieves the effect that the greater the springback error, the stronger the compensation force. When φ1 > φ0, it means that the hole group of the actual blank is denser than the standard state, and the springback error is more obvious. At this time, the ratio of φ1 / φ0 is greater than 1, and the calculated k > k0. The compensation coefficient increases, and the compensation amount k * θn increases synchronously, which can fully cancel the larger springback error and avoid error accumulation. When φ1 < φ0, it means that the hole group of the actual blank is sparser than the standard state, and the springback error is smaller. At this time, the ratio of φ1 / φ0 is less than 1, and the calculated k < k0. The compensation coefficient decreases, and the compensation amount decreases synchronously, avoiding the reverse deviation of the taper caused by over-compensation, and achieving the accurate adaptation of the compensation coefficient to the actual springback error. Therefore, the logic that the compensation coefficient k is positively correlated with the porosity φ not only ensures the pertinence of the compensation, focuses on increasing the compensation force for blanks with high porosity and large springback error, but also avoids the over-compensation problem caused by too large compensation coefficient through formula calculation and the constraint of the correction coefficient, ensuring that the cone angle after each level of compensation can accurately fit the theoretical value; Therefore, this embodiment solves the problems of insufficient compensation, accumulated springback error, and poor consistency of precision between different batches of products caused by porosity changes in existing online compensation processes. By clarifying the positive correlation between the compensation coefficient k and the porosity φ and the specific calculation formula, it achieves coordinated adaptation between online compensation and the porosity of the sheet material. This allows the compensation coefficient to be set differentiated and accurately according to the porosity of the actual billet, ensuring that the compensation force matches the magnitude of the springback error. At the same time, it reduces the impact of subjective operation differences, improves process stability, effectively offsets the springback error after each stage of shaping, avoids taper deviation caused by error accumulation, further improves the stability of taper precision, and reduces processing defects and product scrap rates caused by inaccurate compensation.

[0036] In step S4, the billet, after undergoing multi-stage progressive shaping, is heated to 150℃-300℃ and then placed in a finishing mold for heat and pressure holding for 2-5 minutes. This process effectively eliminates residual stress generated by multi-stage shaping, stabilizes the forming dimensions, eliminates residual errors, and further improves product precision. In step S1, the punching process employs a center-to-outward radial diffusion punching method, with an interval of 0.4s-0.8s between each punching pass. This punching method avoids localized stress concentration in the sheet metal, reduces hole deformation, ensures the consistency of the hole structure, and lays the foundation for subsequent shaping precision control.

[0037] On the other hand, the present invention provides a multi-station processing device for stainless steel kitchenware to realize the above processing method, comprising a pretreatment unit, a multi-stage progressive shaping unit, an online detection and compensation unit, a finishing and calibration unit connected in sequence, and a control system for controlling the coordinated operation of each unit to realize the above processing method. The preprocessing unit includes a punching die and a parameter acquisition module. The punching die is used to perform center-to-outward radial diffusion punching on the billet, and the parameter acquisition module is used to collect the hole distribution parameters and transmit them to the control system. The multi-stage progressive shaping unit includes N stages of progressive shaping dies connected in sequence. The cone angle of each progressive shaping die increases progressively and is electrically connected to the control system. It is used to progressively shape the billet according to the forming cone angle parameters issued by the control system. The online detection and compensation unit includes a springback detection module and a cone angle adjustment module. The springback detection module is used to detect the springback amount of the billet after each stage of shaping and transmit it. The data is sent to the control system. The cone angle adjustment module adjusts the cone angle of the next-stage progressive forming die based on the compensated cone angle calculated by the control system. The finishing calibration unit includes a heating module, a finishing die, and a heat preservation and pressure holding module. The heating module heats the progressively formed billet to 150℃-300℃, the finishing die finishes the heated billet, and the heat preservation and pressure holding module controls the heat preservation and pressure holding time during the finishing process to be 2-5 minutes. The control system receives data from the parameter acquisition module and the springback detection module, and calculates the total number of stages N, the distribution coefficient β, and the compensated cone angle. The system collects parameters and controls each unit to operate according to a preset process. The parameter acquisition module includes an aperture detector, an aperture spacing detector, a plate thickness detector, and a porosity detector, which are used to detect aperture d, aperture spacing p, plate thickness t, and porosity φ, respectively, and transmit the detection data to the control system in real time. The springback detection module uses a laser springback detector, and the cone angle adjustment module uses a servo adjustment mechanism.

[0038] Furthermore, the overall structure can be adapted and improved from the conventional structure of existing stainless steel kitchenware processing equipment, without the need to develop a completely new dedicated structure, thereby reducing equipment development costs and implementation difficulty. The connection methods and installation layout of the pretreatment unit, multi-stage progressive shaping unit, online detection and compensation unit, finishing and calibration unit, and control system for controlling the coordinated work of each unit all adopt the existing mature multi-station equipment layout. Only the existing unit structure is adapted and improved to meet the core requirements of the processing method of this invention.

[0039] The pre-processing unit, as the initial process unit of the processing device, specifically includes a punching die and a parameter acquisition module. Both are installed and connected using an existing mature die + detection module integrated structure. The punching die can be adapted from existing conventional flat punching dies, only requiring adjustment of its punching trajectory to a center-outward radial diffusion type. The punching power mechanism and positioning mechanism of the die both adopt the conventional structure of existing punching equipment. Aperture detectors, hole spacing detectors, plate thickness detectors, and porosity detectors are all conventional industrial testing components that can be directly purchased from the market. They are used to detect hole diameter d, hole spacing p, and plate thickness, respectively. And porosity φ, each detector transmits the detection data to the control system in real time.

[0040] The multi-stage progressive forming unit, as the core unit for realizing the multi-stage progressive forming process, can be adapted and improved from existing multi-stage stamping forming equipment. Specifically, it includes N progressive forming dies connected in sequence. The installation layout and connection method of each progressive forming die follow the conventional layout of existing multi-stage stamping equipment. It is only necessary to adjust the cone angle of the existing conventional cone forming die in stages according to the requirement of "increasing cone angle" in the processing method of this invention, so that the cone angle of each progressive forming die shows an increasing trend and gradually approaches the target cone angle. The forming structure and stamping principle of the die are consistent with the existing cone forming die.

[0041] Both the springback detection module and the cone angle adjustment module utilize existing mature integrated detection and adjustment structures in terms of installation position and signal interaction method. Their positions can be adapted to meet the detection and compensation requirements of this invention. Specifically, the springback detection module employs a conventional laser springback detector; the cone angle adjustment module uses a conventional servo adjustment mechanism, which can be connected to the progressive forming mold via a conventional transmission structure. It only requires precise fine-tuning of the mold's cone angle based on the compensated cone angle calculated by the control system. Its adjustment principle and control method are relatively mature.

[0042] The overall structure of the finishing calibration unit can be adapted and improved from existing stainless steel product finishing equipment. Specifically, it includes common heating modules, finishing molds, and heat preservation and pressure holding modules; the finishing molds can be adapted and improved from existing conventional conical finishing molds; the heat preservation and pressure holding module only needs to have its heat preservation and pressure holding time adjustment range calibrated to 2-5 minutes, while optimizing the constant temperature and pressure control accuracy.

[0043] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "upper," "lower," "left," "right," "front," "back," and similar expressions used in this document are for illustrative purposes only.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A multi-station processing method for stainless steel kitchenware, characterized in that, Includes the following steps: S1: Pre-processing, punching holes in the blank to form a hole group structure, and simultaneously collecting hole group distribution parameters; Based on the pore group distribution parameters, determine the total number of subsequent multi-stage progressive shaping stages N and the allocation coefficient β; S2: Multi-stage progressive shaping, employing a multi-stage progressive forming process to gradually shape the punched blank into the target cone shape. Each stage uses a die with an increasing cone angle, and the forming cone angle corresponding to the die at the nth stage is... Where α0 is the target cone angle, For allocation coefficients; S3: Online detection and compensation; after each stage of shaping, the springback of the blank after stamping is detected. and based on Compensate for the forming cone angle of the next stage: Where k is the compensation coefficient, and ɑn+1 is the theoretical mold cone angle of the (n+1)th stage in S2; S4: Finishing calibration, which performs final finishing on the workpiece after progressive shaping to eliminate residual errors.

2. The multi-station processing method for stainless steel kitchenware according to claim 1, characterized in that, In step S1, the pore group distribution parameters include pore diameter d, pore spacing p, plate thickness t, and porosity φ; in step S1.1, the pore group influencing factors A1=d / t and A2=p / d are calculated using d, p, and t, and the total order N is positively correlated with A1 and φ, and negatively correlated with A2.

3. The multi-station processing method for stainless steel kitchenware according to claim 2, characterized in that, In step S2, when N is greater than the threshold, The value of will decrease as the total number of levels N increases, i.e., the actual distribution coefficient. Where 'a' is the adjustment coefficient, and 'N0' is the total number of standard levels when A1, A2, and φ are all standard values. Let N be the standard distribution coefficient when the total number of levels is the standard value N0, and , .

4. The multi-station processing method for stainless steel kitchenware according to claim 3, characterized in that, In the multi-stage progressive shaping process, the allocation coefficient corresponding to the mold at the (n+1)th stage. Adjust dynamically according to the rebound trend, that is Where θn is the measured rebound amount of the nth level, when n=1, θ0 is the target rebound angle θ, β1=β′, and c is the recursive attenuation coefficient, 0.05≤c≤0.

15.

5. The multi-station processing method for stainless steel kitchenware according to claim 4, characterized in that, The recursive attenuation coefficient c is positively correlated with the porosity φ, that is, the actual recursive attenuation coefficient c = b * c0 * φ1 / φ0; where c0 is the standard recursive attenuation coefficient corresponding to the porosity φ being the standard value φ0, b is the correction coefficient, and φ1 is the actual porosity of the billet.

6. The multi-station processing method for stainless steel kitchenware according to claim 2, characterized in that, In step S3, the compensation coefficient k is positively correlated with the porosity φ, that is, the actual compensation coefficient k = d * k0 * φ1 / φ0; where k0 is the standard compensation coefficient corresponding to the porosity φ being the standard value φ0, d is the correction coefficient, and φ1 is the actual porosity of the billet.

7. The multi-station processing method for stainless steel kitchenware according to claim 1, characterized in that, In step S4, the billet after multi-stage progressive shaping is heated to 150℃-300℃, and then placed in a finishing mold for heat preservation and pressure holding for 2-5 minutes.

8. The multi-station processing method for stainless steel kitchenware according to claim 1, characterized in that, In step S1, the punching process adopts a center-to-outward radial diffusion punching method, and the interval between each punching revolution is 0.4s-0.8s.

9. A multi-station processing apparatus for stainless steel kitchenware for implementing the processing method according to any one of claims 1-8, characterized in that, It includes a preprocessing unit, a multi-stage progressive shaping unit, an online detection and compensation unit, a fine-tuning and calibration unit, and a control system that controls the coordinated operation of each unit, all connected in sequence. The preprocessing unit includes a punching die and a parameter acquisition module, which are used for punching and for acquiring and transmitting hole group distribution parameters, respectively. The multi-level progressive shaping unit contains N levels of progressive shaping molds with increasing cone angles, which are electrically connected to the control system and progressively shape the blank according to the forming cone angle parameters issued by the control system. The online detection and compensation unit includes a springback detection module and a cone angle adjustment module, which are used to detect and transmit the springback amount and adjust the cone angle of the next stage mold according to the compensated cone angle, respectively. The finishing calibration unit includes a heating module, a finishing mold, and a heat preservation and pressure holding module, which are used to heat the billet to 150℃-300℃, finish the billet, and control the heat preservation and pressure holding for 2-5 minutes, respectively. The control system receives relevant data, calculates parameters such as the total number of stages N and the allocation coefficient β, and controls each unit to work according to a preset process.

10. The multi-station processing device for stainless steel kitchenware according to claim 9, characterized in that, The parameter acquisition module includes an aperture detector, an aperture spacing detector, a plate thickness detector, and a porosity detector, which are used to detect the aperture d, aperture spacing p, plate thickness t, and porosity φ, respectively, and transmit the detection data to the control system in real time.

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