Studies on wrinkling and control method in rubber forming using aluminium sheet shrink flanging process

Chen, Lei; Chen, Huiqin; Wang, Qiaoyi; Li, Zhihua

doi:10.1016/j.matdes.2014.09.057

Cited by 27 publications

(17 citation statements)

References 19 publications

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“…FEM for numerical analysis and simulation has become an important tool in predicting material behaviour, collapse, cracking, fracture and fatigue [8,9]. Furthermore, developing analytical models sometimes can be assisted by finite element results [10,11].…”

Section: Springbackmentioning

confidence: 99%

Die design optimization on sheet metal forming with considering the phenomenon of springback to improve product quality

2018

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Abstract. The process of sheet metal forming is one of the very important processes in manufacture of products mainly in the automotive field. In sheet metal forming, it is added a certain size at the die to tolerate a result of the elasticity restoration of material. Therefore, when the product is removed from the die then the process elastic recovery will end within the allowable tolerance size. Extra size of the die is one method to compensate for springback. The aim of this research is to optimize the die by entering a springback value in die design to improve product quality that is associated with accuracy the final size of the product. Simulation processes using AutoForm software are conducted to determine the optimal parameters to be used in the forming process. Variations the Blank Holder Force of 77 N, 97 N, and 117 N are applied to the plate material. The Blank Holder Force application higher than 97 N cannot be conducted because the Forming Limit Diagram indicates the risk of tearing. Then the Blank Holder Force of 37 N, 57 N and 77 N are selected and applied in cup drawing process. Even though a few of wrinkling are appear, however there is no significant deviation of dimension between the product and the design of cup.

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Section: Springbackmentioning

confidence: 99%

Die design optimization on sheet metal forming with considering the phenomenon of springback to improve product quality

2018

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“…Many published studies have investigated the influence of constitutive equations on simulated springback prediction [5,14,22]. For example, Ki-Young Seo et al [14] performed a springback evaluation of TRIP1180 steel sheet.…”

Section: Influence Of the Hardening Modelmentioning

confidence: 99%

“…Making use of these tools, most researches perform a comparison between experimental and simulation studies of the springback effect on flange bending. For example, Lei Chen et al [5] focused their research on straight jogged flange forming, studying the influence of different parameters on the process, such as: sheet thickness, radius of curvature, flanging height, press-time cycle of press, as well as the influence on the results when using different rubber materials in the press (Shore A70 rubber and Shore A80 polyurethane). The influence of the lubricant and the flexible rubber in the hydroforming process of aluminum components was studied in by Paunoui et al [6].…”

mentioning

confidence: 99%

Springback Estimation in the Hydroforming Process of UNS A92024-T3 Aluminum Alloy by FEM Simulations

Churiaque

Sánchez-Amaya

Caamaño³

et al. 2018

Metals

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The production of metal parts manufactured through the hydroforming process is strongly affected by the difficulty in predicting the elastic recovery (springback) of the material. In addition, the formation of wrinkles and crack growth should be avoided. Manual cold work is widely employed in industry to obtain the final shape of the manufactured parts. Therefore, an accurate springback estimation is of high interest to reduce the overall time of manufacturing and also to decrease the manual rectification stage. A working procedure based on finite element simulations (FEM) was developed to estimate the elastic recovery and predict the final morphology of UNS A92024-T3 aluminum alloy pieces after forming. Experimental results of real hydroformed parts were compared with the results obtained in simulations performed with PAM-STAMP software. The influence of different experimental parameters on the forming processes was also analyzed, such as the material properties, the rolling direction of sheet metal, or the hardening criteria employed to characterize the plastic region of the alloy. Results obtained in the present work show an excellent agreement between real and simulated tests, the maximum morphology deviations being less than the thickness of parts (2.5 mm). FEM simulations have become a suitable and mature tool that allows the prediction of the pieces springback, a precise material characterization being required to obtain reliable results.This process has the main advantage of being relatively quick, being also carried out at room temperature. These two factors make it a relatively cheap and convenient process. However, it also presents several inherent technical disadvantages, such as the development of defects (cracks or wrinkles) in areas with high plastic deformation, and the elastic recovery (springback) after the application of pressure. The elastic recovery must be estimated and taken into account, as the final shape of the formed part should be as close as possible to the design part [1]. Therefore, in order to manufacture parts with curved shapes, the dies used must have a more pronounced morphology than the design part, with the aim of compensating the springback. In many cases, the dies geometry is estimated taking into account the intuition and practical experience of the operators, or by means of trial-error tests, which constitute significant losses of time and material, decreasing the overall production rate.As stated before, the hydroforming process involves the generation of residual stresses, high elastic recovery, and the possibility of defects formation, such as wrinkles and cracks. The uncertainty associated with the low precision in the springback estimation usually generates critical variations between machined and design parts, which leads to subsequent manual adjustment of the geometry of the workpiece/part. Most of the studies working on this topic are focused on flange forming [2-4]. One of the emerging methodologies to reduce the possible defects caused in the manufacture of part...

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“…Many methods have been studied to control wrinkling. Chen et al [15] found that three-step forming was a good method for wrinkling control, while the wrinkles cannot be diminished completely when the length of the flange is larger than 40 mm. So the threestep method is not suitable for this case.…”

Section: Wrinkling Control 31 Side Blankholder Controlmentioning

confidence: 99%

“…The simulated results are sensitive to the input parameters such as mesh density, simulation speed, and element type [18]. The optimal solutions involved in FE modeling can be found in [10] and [15]. The results presented and discussed are all based on these optimal input parameters.…”

Section: Simulationmentioning

confidence: 99%

Experimental and numerical studies on the formability of TB5 titanium sheet in rubber cold forming

Chen

et al. 2016

Int J Adv Manuf Technol

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Titanium alloys are often used in aircraft manufacturing. Titanium sheet exhibits low formability and high springback at room temperature, and this causes significant challenges with conventional forming methods. In this study, the phenomena and mechanisms of the formability of TB5 titanium alloys in rubber forming were investigated. It was found that rubber forming was effective for TB5 titanium sheets. Wrinkling in rubber forming was controlled by the side blankholder. The effects of the design parameters of the side blankholder on wrinkling were studied. A typical part was used to investigate the rubber cold forming of TB5. The largest height of the wrinkle became smaller with the increase of the forming pressure, while the hardness of rubber had little effect on the wrinkling. In order to eliminate the wrinkles completely, a wedge was introduced to increase the forming pressure on the shrink flange. Using the wedge, the forming pressure was increased a lot, and the wrinkles were flattened. Springback was controlled by die compensation. Aging treatment was used to increase the strength and part accuracy. After the aging treatment, the internal stress in the cold forming was released. The springback of the flange was corrected.

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Studies on wrinkling and control method in rubber forming using aluminium sheet shrink flanging process

Cited by 27 publications

References 19 publications

Die design optimization on sheet metal forming with considering the phenomenon of springback to improve product quality

Die design optimization on sheet metal forming with considering the phenomenon of springback to improve product quality

Springback Estimation in the Hydroforming Process of UNS A92024-T3 Aluminum Alloy by FEM Simulations

Experimental and numerical studies on the formability of TB5 titanium sheet in rubber cold forming

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