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Schematic of deep drawing model and types of deep drawing die: (a) Deep drawing model; (b) Conventional die; (c) Multi draw-radius die.
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As a major sheet metal process for fabricating cup or box shapes, the deep drawing process is commonly applied in various industrial fields, such as those involving the manufacture of household utensils, medical equipment, electronics, and automobile parts. The limiting drawing ratio (LDR) is the main barrier to increasing the formability and produ...
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... the present research, the multi draw radius die (or so-called MDR die) is proposed to reduce the non-axisymmetric material flow during deep drawing process and prevent fracture as well as to increase in LDR. The schematic of MDR die was shown in Figure 1. The draw radius was designed related to the anisotropy property of the material in each direction along the plane, at 45°, and at 90° to the rolling direction to reduce the nonaxisymmetric material flow during the deep drawing process. ...
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... flange was in a more circular shape. Finally, in the case of conventional die application, the effects of the anisotropy property of the material on material flow were stronger as the deep drawing stroke increased as shown in Figure 8d-1. Vice versa, in the case of MDR die application, the effects of the anisotropy property of the material on material flow were continuously compensated by multi draw radius. ...
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... contrast, Figure 9c shows the MDR die application by designing the larger draw radius positioned for along the plane and at 90° to the rolling direction and the small draw radius positioned for at 45° to the rolling (named MDR type II). The results showed that, in the case of LDR 2.25 (initial blank diameter of 90 mm), the deep drawn parts could be formed by conventional die application as shown in Figure 9a-1. This result corresponded well with the deep drawing theory and literature that by using conventional die application, the deep drawn part could be formed with LDR [1]. ...
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... result corresponded well with the deep drawing theory and literature that by using conventional die application, the deep drawn part could be formed with LDR [1]. The results also showed that the deep drawn parts could be formed by using MDR die application in both cases of MDR die designs as shown in Figure 9b-1,c-1. However, it was observed that in terms of earing defect, the MDR type II showed a larger earing defect than that of MDR type I as well as than that of conventional die application. ...
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... to the anisotropy property of the material in each direction along the plane, at 45°, and at 90° to the rolling direction related to the formability [1], therefore, the design of the larger draw radius positioned at 45° to the rolling direction and the smaller draw radius positioned along the plane and at 90° to the rolling direction was suggested. As shown in Figure 10, the MDR die type II resulted in that the larger non-axisymmetric material flow on flange was formed compared with those in the cases of conventional and MDR die type I applications. As these material flow analyses show, as aforementioned, the non-axisymmetric material flow characteristic on flange and the asymmetry of the flange could be increased and cup wall stretching and fracture were then easier to generate. ...
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... these material flow analyses show, as aforementioned, the non-axisymmetric material flow characteristic on flange and the asymmetry of the flange could be increased and cup wall stretching and fracture were then easier to generate. Figure 11 shows the obtained deep drawn parts with respect to various MDR dies and drawing ratios. The drawing ratios of 2.75 and 2.88 which were larger than LDR were investigated, as respectively shown in Figure 11a,b. ...
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... 11 shows the obtained deep drawn parts with respect to various MDR dies and drawing ratios. The drawing ratios of 2.75 and 2.88 which were larger than LDR were investigated, as respectively shown in Figure 11a,b. On the basis of deep drawing theory [1], the draw radius of 3.5 mm was recommended and then it was set as a small draw radius in MDR die. ...
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... the large draw radius values of 5, 7, and 9 mm were set as the large draw radius. With the drawing ratio of 2.75 as shown in Figure 11a, the results showed that the deep drawn parts could not be achieved when the large radius of 5 mm was set, as shown in Figure 11a-1. This result could be explained by the draw radius of 5 mm, set as the large radius, was too small to reduce the non-axisymmetric material flow characteristic during the deep drawing process. ...
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... the large draw radius values of 5, 7, and 9 mm were set as the large draw radius. With the drawing ratio of 2.75 as shown in Figure 11a, the results showed that the deep drawn parts could not be achieved when the large radius of 5 mm was set, as shown in Figure 11a-1. This result could be explained by the draw radius of 5 mm, set as the large radius, was too small to reduce the non-axisymmetric material flow characteristic during the deep drawing process. ...
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... result could be explained by the draw radius of 5 mm, set as the large radius, was too small to reduce the non-axisymmetric material flow characteristic during the deep drawing process. Conversely, as the large radius was increased, the greater reduction of non-axisymmetric material flow characteristic could be achieved, and then the deep drawn parts could be achieved as for the large radius values set as 7 and 9 mm, as shown in Figure 11a-2,a-3, respectively. The increases in large radius resulted in that, as aforementioned, the non-axisymmetric material flow characteristic on the flange was reduced, and the asymmetry of flange could also be reduced. ...
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... earing defect in the case of large radius 9 mm was smaller than that obtained in the case of the large radius of 7 mm. Next, with the drawing ratio of 2.88 as shown in Figure 11b, the results showed that the deep drawn parts could not be achieved. Namely, owing to the overly large drawing ratio (overly large initial blank diameter) applied, the non-axisymmetric material flow on the flange could not be effectively reduced during a whole deep drawing process. ...
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... addition to the increases in LDR, the quality of deep drawn parts in terms of cup wall thickness and earing defects were also increased. Specifically, the earing defect could be reduced approximately 40% compared with the use of conventional die as shown in Figures 9 and 11. Next, the more uniform cup wall thickness in each direction along the plane, at 45°, and at 90° to the rolling direction could be obtained by comparing with the use of conventional die as shown in Figure 12. ...
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... the earing defect could be reduced approximately 40% compared with the use of conventional die as shown in Figures 9 and 11. Next, the more uniform cup wall thickness in each direction along the plane, at 45°, and at 90° to the rolling direction could be obtained by comparing with the use of conventional die as shown in Figure 12. However, the MDR die should be strictly design related to the anisotropy property of the material in each direction along the plane, at 45°, and at 90° to the rolling direction which was suggested in the previous section. ...
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... validate the accuracy of the MDR die application obtained by FEM simulation, the FEM simulation results were compared with those obtained by experimental results, as shown in Figure 13. The FEM simulation results showed that the predicted deep drawn parts corresponded well with the experiments as shown in Figure 13a-1,b-1 in the cases of MDR draw radius of 3.5-7 and 3.5-9 mm, respectively. ...
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... validate the accuracy of the MDR die application obtained by FEM simulation, the FEM simulation results were compared with those obtained by experimental results, as shown in Figure 13. The FEM simulation results showed that the predicted deep drawn parts corresponded well with the experiments as shown in Figure 13a-1,b-1 in the cases of MDR draw radius of 3.5-7 and 3.5-9 mm, respectively. In terms of cup wall thickness, the FEM simulation results showed that the predicted cup wall thickness corresponded well with the experiments as shown in Figure 13a-2,b-2 in the cases of MDR draw radius of 3.5-7 and 3.5-9 mm, in which the errors in the analyzed cup wall thickness were approximately 3% compared with the experimental results. ...
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... FEM simulation results showed that the predicted deep drawn parts corresponded well with the experiments as shown in Figure 13a-1,b-1 in the cases of MDR draw radius of 3.5-7 and 3.5-9 mm, respectively. In terms of cup wall thickness, the FEM simulation results showed that the predicted cup wall thickness corresponded well with the experiments as shown in Figure 13a-2,b-2 in the cases of MDR draw radius of 3.5-7 and 3.5-9 mm, in which the errors in the analyzed cup wall thickness were approximately 3% compared with the experimental results. ...
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Citations
... Forming methods based on material deformation have become crucial in the mechanical industry, particularly in sheet metal forming for automotive products [1][2][3]. The deep drawing process, a widely used technique, is influenced by various factors such as material characteristics, mold texture, process parameters, technology, and mold friction [4][5][6]. However, issues such as wrinkles, fractures, and thinning often arise, requiring significant effort and resources for resolution [7][8][9]. ...
... Simulations and experiments have also focused on controlling wrinkling and improving formability using varying workpiece thickness and different dies [5,16]. Additional research has investigated defects in cup rims and the use of specific dies to rectify these defects [18], as well as the influence of key factors such as punch speed, blank holder force, friction coefficient, and starting temperature on deep drawing processes [19]. ...
... Additionally, the performance of the Kim-Tuan model was compared with the hardening models proposed by Swift [44] and Voce [45], as shown in Fig. 1 b, using Eqs. (5) and (6) respectively. The coefficients of the Swift and Voce hardening models were determined as follows: C = 584.4 ...
This study aims to accurately select a yield criterion by utilizing the identification coefficient method to describe anisotropic behavior using material parameters and finite element simulation. The influence of anisotropy is investigated and compared with experimental data. Three yield functions, namely von Mises, Hill’48R, and Hill’48S, are analyzed and their impact on numerical results is investigated using the Kim-Tuan stress–strain model for hardening law. The SPCC material (cold-rolled mild steel) is used for experimental validation. The main variables under study are the fracture height of cylinder cups and the evolution of simulated punch force. The deep drawing process of SPCC cylindrical cups is simulated using the finite element method (FEM) to evaluate the impact of the yield criterion on fracture height. The predicted punch force evolution remains consistent regardless of the yield criterion used, but the fracture height of cylinder cups is significantly influenced by the choice of yield criterion. The von Mises yield criterion leads to a significantly lower fracture height, while the Hill’48S yield criterion yields a fracture height that is too high. However, the results demonstrate that the Hill’48R yield criterion exhibits the most favorable agreement with experimental data for the fracture height of cylinder cups in deep drawing process. Additionally, the study investigates the influence of process parameters such as blanking holder force (FBH), nose radius of the punch (Rp), and limiting drawing ratio (Mt) on fracture height and addresses optimization problems. A highly accurate mathematical model is developed to predict fracture height based on FBH, Rp, and Mt, achieving a deviation of only 4.81% when compared to corresponding experimental values. These findings contribute significantly to the advancement of sheet metal forming technology in various industries, particularly in reducing defective product rates.
... In terms of the cutting process, improvements in the cut-edge quality by reducing rollovers, cracks, and burrs have mainly been achieved [8][9][10][11][12][13][14]. In terms of the deep-drawing process, many studies have been performed to increase the deep-drawn-component quality by decreasing various defects, such as material thinning [15][16][17][18][19][20] and the earing defect [21][22][23][24][25]. Many researchers and engineers have also conducted their research based on experiments and FEM approaches to form intricately shaped deep-drawn components out of difficult-to-form materials, such as stainless steels and aluminum alloys [26][27][28]. ...
The competition among sheet-metal-forming manufacturers in recent years has become more severe. Many manufacturers have survived by cutting their production costs. Increasing the formability, which could reduce the production costs, is the focus of many manufacturers and engineers. In the present research, to increase the formability over the limiting drawing ratio (LDR) in the cylindrical deep-drawing process, the application of oleophobic coating is proposed. An SUS304 (JIS standard)-stainless-steel cylindrical deep-drawn component was used as the investigated model. First, we applied the oleophobic coating in the sheet-metal-forming process, and tribology tests were carried out to examine the friction coefficients, which were reduced by approximately 60% compared with those of standard lubricant use (Iloform TDN81). Next, deep-drawing tests were performed to investigate the drawing ratio (DR). The LDR recommended in the past could be overcome, and it increased by approximately 12% with the oleophobic coating use. Finally, the deep-drawing mechanism using an extremely low friction coefficient was clarified as well. Based on these results, an oleophobic coating could be applied in the cylindrical deep-drawing process to increase the LDR. The results also clearly expose the multidisciplinary approach that combines an oleophobic coating application and the sheet-metal-forming process.
... For example, surface roughness of the metal and friction during the forming process, as well as plastic flow stress and spring-back, are very important. This makes accurate prediction and control of the parameters in micro forming processes very important [3,4]. ...
Deep drawing is a method of shaping flat sheets into geometrically cup-shaped metal stock, known as blanks, without failure or excessive localised thinning. When compared to other metal forming methods, deep drawing has a wide range of applications. It is widely used in the industries, among which are beverage and food cans, kitchen sinks, cookware, engine oil pans, Solenoid assemblies, automotive fuel tanks as well as fire extinguisher containers. Deep drawing is the most difficult procedure in manufacturing to obtain a faultless result. Because there is very little material waste, it is a very cost-effective technique. Defects, both in shape and location, are dimensionally deviant and constitute a significant difficulty for companies that produce large quantities of their products. In this mini-study, an overview of the deep drawing technique was investigated. The review covered the applications, merits, and demerits of the deep drawing process. Different defects in deep drawing such as wrinkling, ironing, tearing, earing, galling etc were briefly discussed. A brief history and the advances that have been made in deep drawing was established.
... The material was assumed to be planar anisotropic. 3. ...
To manufacture metal products of accurate size and shape by deep drawing requires the precise control of a number of variables. The problem of spring-back after the load has to be avoided, and the prevention of cracks in the product requires careful control of the punch load. In this study, where drawing experiments and simulations were carried out on thin sheets of SUS304 stainless steel, the influence of the scale effect on the thin sheets also needed consideration. This was accomplished by the use of an updated Lagrangian formulation and finite element analysis. Material behavior was simulated using a micro-elastoplastic material model, the performance of which was compared with that of models involving conventional materials. The Dynaform LS-DYNA solver was used for simulation analysis, and pre and postprocessing were carried out to obtain material deformation history as well as to determine thickness change, distribution and material stress, and prepare strain distribution maps. Scaling was necessary to account for the effect of the thickness of the sheet and the relationship between punch load and stroke, the distribution of thickness, stress and strain, and the maximum size (d) of the flanged hole and the maximum height of the flange. The simulation results were compared with experimental results to confirm the accuracy of the three-dimensional finite element analysis of the elastoplastic deformation. The results showed that the size of the fillet radius of the hole (Br) had an effect on the punch load, which increased with an increase in Br. However, the minimum thickness of the formed flange decreased with an increase in Br. The maximum principal stress/strain and height of the flange also increased with an increase in Br. The punch fillet radius (Rp) also had an impact on the process. The punch load decreased with the increase in Rp, while the minimum thickness increased slightly. The average values of the minimum thickness for three models were 0.148, 0.0775, and 0.0374 mm. The forming ratio also had an influence on the process. When the forming limit of the square hole flange was FLR = 0.84, cracking occurred in the corners of the flange, and wrinkles formed over the undrawn area of the sheet. These findings can serve as a valuable reference for the design of deep drawing processes.
... The 'punch with microridges' technique could be applied to shorten the multistage deep drawing process [18]. Based on this literature and forming theory [30][31][32], the formability of sheet metal is usually explained via forming mechanisms, i.e., material flow and stress distribution analyses. In addition, the formability of sheet metal is dependent on the forming process parameters, i.e., blank-holder pressure, lubricants, and draw radius, as well as the types of shape parts, i.e., cylindrical or box shapes. ...
... In recent years, research has been focused on setting different process parameters related to the forming mechanism on each deformation zone during the deep drawing process. However, there were a few studies in the past [31][32][33][34] that were performed by setting different draw radii related to the forming mechanism in the cylindrical deep drawing process to increase the limiting drawing ratio (LDR) [32] and to prevent earing defects [31]. Other studies were performed by segmenting blank-holders with pressure control to obtain better formability of deep drawn parts [33,34]. ...
... In recent years, research has been focused on setting different process parameters related to the forming mechanism on each deformation zone during the deep drawing process. However, there were a few studies in the past [31][32][33][34] that were performed by setting different draw radii related to the forming mechanism in the cylindrical deep drawing process to increase the limiting drawing ratio (LDR) [32] and to prevent earing defects [31]. Other studies were performed by segmenting blank-holders with pressure control to obtain better formability of deep drawn parts [33,34]. ...
The ‘formability’ of sheet metal is a major keyword referring to process design in the sheet metal forming industry. Higher formability could reflect lower production costs and time. Many studies have been carried out to improve formability in various ways, by using the finite element method and experimental approaches. In the present research, a new zoning lubricant technique is proposed. The stainless steel SUS304 square deep drawn box is used as an investigative model. Based on the material flow analysis, we found that zoning lubricant die application could reduce the difference in material flow velocity between wall and corner zones. This material flow characteristic resulted in decreased nonconcurrent plastic deformation during the deep drawing process, as well as decreased stretching in the cup wall and the delaying of the fracture. In the present research, the design of the zoning lubricant die was strictly concerned with achieving functionality related to the friction coefficient, area of zoning, and blank-holder pressure. A smaller friction coefficient positioned in the corner zone and larger friction coefficient positioned in the wall zone are recommended. It was revealed that, by appropriate zoning lubricant die application, formability could be increased in terms of box height by approximately 7 mm or 10%.
... These thickness distribution results agreed well with the thickness strain distribution results calculated on the basis of the deformed grain size. These results also corresponded well with the deep drawing theory and literature [18,19]. Next, in terms of radial strain and circular strain distributions, the radial strain was positive, but the circular strain was negative. ...
... They agreed well with radial and circular strain distributions calculated on the basis of the deformed grain size. These results also corresponded well with the deep drawing theory and literature [18,19]. As a result, based on the microstructure evolutions and strain distributions, the occurrence of earing defects could be clearly clarified. ...
... This resulted in the restriction of material flown into the die due to the highly excessive elongating material flow into these directions from other portions. Then, the nonaxisymmetric material flow characteristic on the flange portion during the deep drawing process was generated [18]. These plastic deformation and material flow characteristics caused the material in the direction along the plane and at 90° to the rolling direction were easier to stretch compared to that in direction at 45° to the rolling direction, and then, the earing defects were formed. ...
In recent years, the old-fashioned cylindrical cup shapes are still widely used, and there are many defects which could not be solved yet. In the present research, the classical earing defects, which are mainly caused by the material mechanical property of the anisotropic property of the material (R-value), are focused on. The multi draw radius (MDR) deep drawing die is applied and investigated to achieve nearly zero earing defects by encountering the R-value during the deep drawing process. Based on the experiments, in different directions in the sheet plane, the somewhat concurrent plastic deformation could be controlled, and the uniform elongated grain microstructure and uniform strain distributions on the cup wall could be achieved. Therefore, on the basis of these characteristics, the earing defects could be prevented, and the nearly zero earing defects could be achieved. However, to achieve the nearly zero earing defects, the suitable MDR die design relating to the R-value should be strictly considered. In the present research, to apply the MDR die for the medium carbon steel sheet grade SPCC cylindrical drawn cup, the following was recommended: the large draw radius positioned at 45° to the rolling direction and the small draw radius positioned along the plane and at 90° to the rolling direction. Therefore, in the present research, it was originally revealed that the nearly zero earing defects could be successfully performed on the process by using the MDR die application.
This study aimed to investigate the effect of elevated temperatures, combined with the blank holder force and punch radius, on the thickness distribution of cylindrical cups in the deep drawing of SPCC sheet steel. Numerical simulations and corresponding experiments were conducted to evaluate the performance of the hardening equation that combines anisotropy coefficient based on Hill’s 48 stress models in simulating and comparing the deformed cylindrical cup shapes at room and elevated temperatures. The results showed good agreement between simulation and experimental data and confirmed that the thinness of the cylindrical cup increased at elevated temperatures due to the indeterminacy of the blank holder force parameter. To improve the thickness uniformity of the cylindrical cups, the Taguchi analysis design and ANOVA variance were employed to optimize the blank holder force, punch radius, and elevated temperature parameters. The optimal parameters were selected for simulation and experiment to confirm the uniformity of the cup thickness, with a thickness deviation of only 1.62% between simulation and experiment. This study provides valuable insights into the process parameters and conditions necessary for the deep drawing of cylindrical cups with uniform thickness distribution.
Earing has been a major issue in the deep-drawing process, especially for cylindrical cups. The additional work required to fabricate the cylindrical cup according to its specifications is frequently caused by these defects. Only a few methods have been developed to eliminate these defects, despite knowing the origin of these defects to be the material's anisotropic mechanical property (R-value). In this study, we proposed a zoning lubricant technique to achieve practically zero earing defects by applying a varied friction coefficient in relation to the R-value. This technique was examined based on experimental work and the finite-element method (FEM). The deep-drawing process for achieving practically zero earing defects was evident based on the FEM simulation findings. This resulted in practically no earing defects being discovered, and earing defects were avoided as a result of these characteristics. However, to accomplish almost zero earing defects, the proper design of zoning lubricant uses connected to the R-value should be properly considered. According to these findings, a smaller friction coefficient should be placed along the plane and at 90° to the rolling direction, whereas a larger friction coefficient should be positioned at 45° to the rolling direction. Furthermore, it was initially discovered in the current investigation that the use of zoning lubricant could successfully execute the procedure with nearly zero earing defects.
