scholarly journals Effects of Variable Punch Speed and Blank Holder Force in Warm Superplastic Deep Drawing Process

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 493
Author(s):  
Ken-ichi Manabe ◽  
Kentaro Soeda ◽  
Akinori Shibata

A cylindrical deep drawing test was conducted for the purpose of improving the drawability, product accuracy, and quality in warm deep drawing using a superplastic material with large strain rate dependence. Then, the effects of blank holding force (BHF) and punch speed (SPD) on the flange wrinkle behavior and wall thickness distribution were investigated by experiments and theoretical analysis. A Zn-22Al-0.5Cu-0.01Mg alloy superplastic material SPZ2 with a sheet thickness of 1 mm was employed as the experimental material, and a cylindrical deep drawing experiment with the drawing ratio (DR) of 3.1 and 5 was performed at 250 °C. A good agreement was qualitatively obtained between the elementary theory on the flange wrinkle limit, the fracture limit, and the experimental results. In addition, the authors examined each variable BHF and SPD method obtained from the theory and experimentally demonstrated that the variable BHF method has a great effect on uniform wall thickness distribution and that variable SPD has a great effect on shortening the processing time for superplastic materials. Furthermore, the authors demonstrated the effectiveness of the variable BHF/SPD deep drawing method that varies both BHF and SPD simultaneously.

Author(s):  
Ihsan Irthiea ◽  
Zaid Mahmood

Due to its simplicity, versatility of process and feasibility of prototyping, using flexible tools in sheet forming seems appropriate for producing cups at microscales. This article presents a novel micro deep drawing technique in which a cooperation of a floating ring, as a primary rigid die, with a rubber pad, as a main flexible die, is employed for forming micro-cups. The function of the floating ring is to overcome minor wrinkles that commonly occur at flange portion, while the flexible die is to complete the forming stroke. The influence of initial sheet thickness, drawing ratio, punch corner radius and rubber height is studied through simulations and experiments. Furthermore, three size scales are adopted to investigate the possibility of using the proposed technique under different process dimensions. The code ABAQUS/Standard is utilized to build the finite element models and thereafter micro-forming experiments are carried out to verify the numerical results. For this purpose, a special setup is developed to be compatible with simulation models. The results show that the formed cups are characterized by very accurate dimensions, high surface quality, homogeneous wall thickness distribution in terms of maximum thinning and thickening and relatively large aspect ratio.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3993
Author(s):  
Thanh Trung Do ◽  
Pham Son Minh ◽  
Nhan Le

The formability of the drawn part in the deep drawing process depends not only on the material properties, but also on the equipment used, metal flow control and tool parameters. The most common defects can be the thickening, stretching and splitting. However, the optimization of tools including the die and punch parameters leads to a reduction of the defects and improves the quality of the products. In this paper, the formability of the camera cover by aluminum alloy A1050 in the deep drawing process was examined relating to the tool geometry parameters based on numerical and experimental analyses. The results showed that the thickness was the smallest and the stress was the highest at one of the bottom corners where the biaxial stretching was the predominant mode of deformation. The problems of the thickening at the flange area, the stretching at the side wall and the splitting at the bottom corners could be prevented when the tool parameters were optimized that related to the thickness and stress. It was clear that the optimal thickness distribution of the camera cover was obtained by the design of tools with the best values—with the die edge radius 10 times, the pocket radius on the bottom of the die 5 times, and the punch nose radius 2.5 times the sheet thickness. Additionally, the quality of the camera cover was improved with a maximum thinning of 25% experimentally, and it was within the suggested maximum allowable thickness reduction of 45% for various industrial applications after optimizing the tool geometry parameters in the deep drawing process.


2021 ◽  
Vol 6 (4) ◽  
pp. 251-261
Author(s):  
Manh Tien Nguyen ◽  
Truong An Nguyen ◽  
Duc Hoan Tran ◽  
Van Thao Le

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes.


1977 ◽  
Vol 18 (4) ◽  
pp. 340-346 ◽  
Author(s):  
Hiroshi Tanaka ◽  
Masaru Sato ◽  
Kazunari Yoshida

2012 ◽  
Vol 457-458 ◽  
pp. 1219-1222 ◽  
Author(s):  
Yu Zhu ◽  
Min Wan ◽  
Ying Ke Zhou ◽  
Qing Hai Liu ◽  
Nan Song Zheng ◽  
...  

Hydrodynamic deep drawing (HDD) is an effective method for manufacturing complicated and thin-walled parts. Aiming at the forming process of the stainless steel part with 0.4 mm thick and complex stepped geometries, the technology scheme of multi-stage HDD assisted by conventional deep drawing (CDD) is proposed in consideration of wrinkling and destabilization in the unsupported region of the conical wall, and finite element models are built. As a key process parameter, pre-forming depth on the quality of the parts is explored with assistance of numerical simulations and verification experiments. Furthermore, the failure modes, including wrinkling and fracture during forming process are discussed; meanwhile, the optimum pre-forming depth is realized. The results indicate that the technological method is proven to be feasible for integral forming of thin-walled parts with a large drawing ratio and stepped geometries; moreover, the parts with uniform thickness distribution and high quality are successfully formed by adopting optimum pre-forming depth.


1997 ◽  
Vol 37 (1) ◽  
pp. 178-182 ◽  
Author(s):  
A. Aroujalian ◽  
M. O. Ngadi ◽  
J-P. Emond

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