scholarly journals Erratum: “A Simplified Approach to Estimate Limiting Drawing Ratio and Maximum Drawing Load in Cup Drawing” [Journal of Engineering Materials and Technology, 2004, 126(1) pp. 116–122]

2004 ◽  
Vol 126 (3) ◽  
pp. 325-325
Author(s):  
Daw-Kwei Leu and ◽  
Jen-Yu Wu
Keyword(s):  
Drawing Ratio ◽  
Simplified Approach ◽  
Limiting Drawing Ratio ◽  
Engineering Materials ◽  
Cup Drawing

A Simplified Approach to Estimate Limiting Drawing Ratio and Maximum Drawing Load in Cup Drawing

2004 ◽  
Vol 126 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Daw-Kwei Leu ◽  
Jen-Yu Wu
Keyword(s):  
Friction Coefficient ◽  
Strain Hardening ◽  
Sheet Metal ◽  
Elementary Theory ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Normal Anisotropy ◽  
Limiting Drawing Ratio ◽  
Special Cases ◽  
Cup Drawing

A new and practically applicable equation, including the normal anisotropy R, the strain hardening exponent n, the friction coefficient μ, and the bending factor t0/rd for estimating the limiting drawing ratio LDR (a measure of drawability of sheet metal) in cup drawing of a cylindrical cup with a flat-nosed punch is derived by an elementary theory of plasticity in an explicit form. Whiteley’s and Leu’s equations for estimating the LDR, and Hill’s upper limit value of LDR, all are the special cases of the derived equation. The estimation of LDR agrees well with the experiment. It is shown that the most important parameters for LDR are the normal anisotropy R and friction coefficient μ, however the strain hardening exponent n has little effect on the LDR. On the other hand, a new and simple equation, incorporating the derived LDR and the critical drawing load Pc, for estimating the maximum drawing load Pd at a certain drawing ratio is derived. It also agrees well with the experiment. It is thereby possible to better understand and control the drawing limit of sheet metal in industry necessity.

Cup Drawing from an Anisotropic Blank

1969 ◽  
Vol 91 (3) ◽  
pp. 766-771 ◽  
Author(s):  
W. A. Mir ◽  
M. J. Hillier
Keyword(s):  
Hydrostatic Pressure ◽  
Drawing Ratio ◽  
Blank Holder ◽  
Limiting Drawing Ratio ◽  
Cup Drawing ◽  
Good Agreement

Tests on aluminum, copper and brass blanks indicate that, provided proper hold-down methods are used, the limiting drawing ratio that can be obtained is almost independent of type of blank holder. A comparison of theoretical and experimental critical punch loads at failure shows that, for aluminum, good agreement can be obtained when drawing under all-round hydrostatic pressure. This method produces a reduction in die friction and a significant increase in limiting drawing ratio. There is an optimum hydrostatic pressure above which no advantage is to be obtained.

scholarly journals Multi Draw Radius Die Design for Increases in Limiting Drawing Ratio

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 870 ◽  
Author(s):  
Wiriyakorn Phanitwong ◽  
Sutasn Thipprakmas
Keyword(s):  
Deep Drawing ◽  
Material Flow ◽  
Rolling Direction ◽  
Die Design ◽  
Drawing Ratio ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Limiting Drawing Ratio ◽  
Proper Design ◽  
Main Barrier

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 production rate as well as to decrease production cost and time. In the present research, the multi draw radius (MDR) die was proposed to increase LDR. The finite element method (FEM) was used as a tool to illustrate the principle of MDR based on material flow. The results revealed that MDR die could reduce the non-axisymmetric material flow on flange and the asymmetry of the flange during the deep drawing process. Based on this material flow characteristic, the cup wall stretching and fracture could be delayed. Furthermore, the cup wall thicknesses of the deep drawn parts obtained by MDR die application were more uniform in each direction along the plane, at 45°, and at 90° to the rolling direction than those obtained by conventional die application. In the present research, a proper design for the MDR was suggested to achieve functionality of the MDR die as related to each direction along the plane, at 45°, and at 90° to the rolling direction. The larger draw radius positioned for at 45° to the rolling direction and the smaller draw radius positioned for along the plane and at 90° to the rolling direction were recommended. Therefore, by using proper MDR die application, the drawing ratio could be increased to be 2.75, an increase in LDR of approximately 22.22%.

Cup-drawing from a Flat Blank: Part I. Experimental Investigation

1951 ◽  
Vol 165 (1) ◽  
pp. 199-211 ◽  
Author(s):  
S. Y. Chung ◽  
H. W. Swift
Keyword(s):  
Experimental Investigation ◽  
Drawing Ratio ◽  
Drawing Process ◽  
Low Carbon ◽  
Deep Drawing Process ◽  
Comparative Tests ◽  
Descriptive Account ◽  
Nominal Capacity ◽  
Die Profile ◽  
Cup Drawing

Part I gives an account of an experimental investigation of the forces, work and strains involved, and the conditions for successful drawing of a cylindrical shell from a flat circular blank. It is claimed that the results are sufficiently accurate to provide a basis of reference for theoretical treatments of cup-drawing, as well as an empirical basis of comparison between different drawing conditions. The work was carried out in an experimental crank-press of 50 tons nominal capacity, and was based on a cup diameter of 4 inches. Blank thicknesses from 0·025 to 0·060 inch were used, and although most of the work was carried out on a low-carbon rimming steel, comparative tests were made with aluminium, brass, and copper, of different tempers. The conditions examined included methods of blank-holding, drawing ratio, punch and die profile radii, punch-die clearance, and blank thickness. Although this part has no theoretical pretensions, it includes a descriptive account of stresses and strains in the deep-drawing process, based on plastic theory.

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