1 Introduction
As one of the light metals, aluminum is vital to the aeronautical
industry, and given the increasing fuel costs, designing,
and constructing lighter automobiles are among the major
concerns of the future automotive industry.
Replacing steel with aluminum results in considerably reduced structural
weight, improved corrosion resistance, and increased
strength–weight ratio.
Therefore, the material has achieved
widespread use in major industries, mainly in sheet-forming
processes.
However, the lower formability coefficient, particularly
in the case of thin sheets, is a drawback restricting
its universal substitution for steel.
Thus, improved and optimized
parameters of deep drawing as one of the main sheet
forming processes is important in order to prevent common
defects of the process in this metal.
In deep drawing process,
excessive mass flow causes wrinkling while insufficient
mass flow is associated with fracture.
Regarding the essential
role of blankholder and its direct influence on mass flow into
die’s hole, major portion of the recent investigations into
deep drawing process concentrates on improving, and
employing new blankholder techniques. Thus, Koyama
et al