The Optimization of Variable Blank Holder Force for Sheet Metal Stamping

2006 ◽  
Author(s):  
Wu-Rong Wang ◽  
Guan-Long Chen
Keyword(s):  
Fem Simulation ◽  
Hydraulic Press ◽  
Alloy Sheet ◽  
Optimization Strategy ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Variable Blank Holder Force ◽  
Metal Stamping ◽  
New Strategy ◽  
Blank Holding Force

This paper focuses on the research of blank holding force (BHF) and proposes a new strategy to optimize the variable BHF and determine the drawing limit under the variable BHF. The optimization strategy is based on the analysis of BHF formability window and integrated into FEM code to obtain time or/and spatial optimal BHF that applies on binders. And then a stepped rectangular box of 60 mm drawing height with segmented binders and a cylinder cup without die bottom are adopted to validate the optimization strategy. Firstly, constant BHF FEM simulations through careful experiment design are conducted to discover the drawing limit height under maximum constant BHF. Secondly, FEM simulation combining the new BHF optimization strategy is carried and the optimal profile of variable BHF is determined for both step box and cylinder cup during the whole punch stroke. The result shows this stepped box could be formed successfully using 5754-0 aluminum alloy sheet, while the maximum drawing height under constant BHF is 45mm. And the drawing limit of cylinder box under optimal BHF could reach the drawing height of 61mm, which is greatly increased comparing with maximum of 47mm under constant BHF. Finally, the constant BHF experiment and the derived trajectory of optimal BHF of both geometries are verified on a multipoint variable BHF hydraulic press and the experiment results correspond well with those of FEM simulation. This new BHF optimization strategy not only helps to determine time and spatial optimal BHF for known geometry, but also assists to design maximum drawing height for unknown geometry, which makes it an effective method.

Research on Deep Drawing with Multi-Point Variable Blank-Holder Force Controlling by Computer

2012 ◽  
Vol 472-475 ◽  
pp. 645-648
Author(s):  
Ming Ming Ding ◽  
Yong Huang ◽  
Yu Qing Shi
Keyword(s):  
Deep Drawing ◽  
Low Cost ◽  
Hydraulic Press ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Variable Blank Holder Force ◽  
Blank Holding Force ◽  
Working Principle ◽  
Cylindrical Cup ◽  
Set Up

On the basses of analyzing the defects of variable blank holder force hydraulic press on construction and its rigid being not enough,the realization of designing method,working principle,hydraulic and system for ne controlling w type upper multi-point deep drawing with variable blank—holding force controlled by computer was introduced.In order to verify the effect of application of this set up,the testing results of deep drawing a rectangular box and a cylindrical cup formed component was presented. The results show that the equipment has low cost, general in using and optimal efficient of controlling.

Experimental Research on Warm Deep Drawing of Magnesium Alloy Sheet by Variable Blank Holder Force Control

2007 ◽  
Vol 546-549 ◽  
pp. 285-288
Author(s):  
Qun Feng Chang ◽  
Ying Hong Peng ◽  
Da Yong Li ◽  
Xiao Qin Zeng
Keyword(s):  
Magnesium Alloy ◽  
Deep Drawing ◽  
Hydraulic Press ◽  
Alloy Sheet ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Variable Blank Holder Force ◽  
Warm Deep Drawing ◽  
Working Principle ◽  
And Control

A process of warm deep drawing of magnesium alloy with variable blank holder force has been presented in this study. A hydraulic press that can realize adjustable blank holder forces was developed and its working principle and control system introduced. A warm deep drawing mould was fixed and warm deep drawing experiments are conducted on the hydraulic press. Different variation schemes of the blank holder force with the stroke of the punch was tested, and compared with experiment results. The experimental results show that adopting the variable blank holder force technique can remarkably improve the forming performance and decrease the reduction ratio of thickness from 15.21% to 12.35%. It is further demonstrated that the suitable blank holder force variation scheme is an inverted V curve with the punch stroke.

Numerical Simulation of Warm Deep Drawing of AZ31 Magnesium Alloy Sheet with Variable Blank Holder Force

2007 ◽  
Vol 340-341 ◽  
pp. 639-644 ◽  
Author(s):  
Ying Hong Peng ◽  
Qun Feng Chang ◽  
Da Yong Li ◽  
Hu Jie ◽  
Xiao Qin Zeng
Keyword(s):  
Numerical Simulation ◽  
Magnesium Alloy ◽  
Deep Drawing ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Magnesium Alloy Sheet ◽  
Variable Blank Holder Force ◽  
Az31 Magnesium Alloy Sheet

Blank holder force (BHF) plays an important role in sheet metal forming. Previous studies demonstrated that variable blank holder forces can improve the cold formability of steel blank, but the research on the application of variable blank holder force in warm forming of magnesium sheet forming has not been well investigated. In this study, the mechanical property of AZ31 magnesium alloy sheet is measured through some uniaxial tensile tests. In order to obtain the variational rule of the BHF, a mathematical model of BHF is deduced based on the energy theory. The variational rule of the BHF over the punch stroke is analyzed. Finally, three profiles of the BHF curve are designed, and the numerical simulation of warm deep drawing process of magnesium alloy sheet is also performed. A suitable variable blank holder force scheme is obtained through comparison among three results of simulation. The simulation indicates that the limiting drawing ratio of AZ31 magnesium alloy sheet can be improved from 3.0 to 3.5 with the suitable blank holder force varied by an inverted V curve.

Sign in / Sign up

Export Citation Format

Share Document