abstract
In this paper, a new method was proposed in order to enhance the limiting drawing ratio (LDR) ofAA5754-
O in the hydromechanical deep drawing process (HDD). In the proposed method, a shallow drawbead
was added to the blank holder to increase LDR so as to provide strain hardening of a large region on the
flange of the sheet material in addition to pre-bulging process which affects particularly only the initial
stage but not the later ongoing process. So the LDR of the AA5754-O was increased from 2.65 to 2.787
by enlarging the region of strain hardening in the flange and partially reducing wrinkling tendency due
to occurred tensile stresses using the convenient pressure and blank holder force profiles. The importance
levels and their convenient values for height of drawbead, pre-bulge height and pressure, surface
roughness of the punch were determined with analysis of variance (ANOVA) is a statistical method.
ANOVA analysis illustrated that adding a shallow drawbead to the blank holder is the most effective
factor between the investigated factors for the HDD process. While the effects of the pre-bulging pressure
and pre-bulging height were determined as quite small, the surface roughness of the punch was
found unimportant compared to the effect of the shallow drawbead. The highest LDR value was obtained
with 1 mm drawbead height, 5 mm pre-bulging height, 10 MPa pre-bulging pressure and 2.8 m surface
roughness of the punch.
abstractIn this paper, a new method was proposed in order to enhance the limiting drawing ratio (LDR) ofAA5754-O in the hydromechanical deep drawing process (HDD). In the proposed method, a shallow drawbeadwas added to the blank holder to increase LDR so as to provide strain hardening of a large region on theflange of the sheet material in addition to pre-bulging process which affects particularly only the initialstage but not the later ongoing process. So the LDR of the AA5754-O was increased from 2.65 to 2.787by enlarging the region of strain hardening in the flange and partially reducing wrinkling tendency dueto occurred tensile stresses using the convenient pressure and blank holder force profiles. The importancelevels and their convenient values for height of drawbead, pre-bulge height and pressure, surfaceroughness of the punch were determined with analysis of variance (ANOVA) is a statistical method.ANOVA analysis illustrated that adding a shallow drawbead to the blank holder is the most effectivefactor between the investigated factors for the HDD process. While the effects of the pre-bulging pressureand pre-bulging height were determined as quite small, the surface roughness of the punch wasfound unimportant compared to the effect of the shallow drawbead. The highest LDR value was obtainedwith 1 mm drawbead height, 5 mm pre-bulging height, 10 MPa pre-bulging pressure and 2.8 m surfaceroughness of the punch.
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