Page 46 - MetalForming May 2017

Die Development and Simulation Software
that a dozen years ago, die simulation merely was animating what would hap- pen in a die, without any true interac- tion between the die components or even with the die components and the strip. Today, several simulation-soft- ware packages display very realistic die-operating conditions.
“Some of the software,” Proeber says, “can duplicate the conditions taking place in a 20-ft.-long transfer die, right
down to predicting press speed for a given die, even before it hits the press. The tools within the software even account for velocity and acceleration.
“When people hear the word sim- ulation, they often get nervous thinking that the software will be difficult to learn, to set up and to pay for,” Proeber adds. “This definitely is not always the case. The time savings downstream typically pays for itself many times
over, based on the ability to detect col- lision problems and clearance issues before the die ever enters the press— much more efficient than catching and fixing problems later.”
Case Study: Development and Optimization of a Deep-Drawn Transfer-Case Cover
Last but not least, all of the lessons learned come together with this case study presented by Peter Ulintz.
“Problems such as wrinkling, exces- sive local thinning and springback were investigated when forming a nonsym- metrical transfer-case cover,” he explains. “Wrinkling in the unsupported region between the punch and die was eliminated by placing various shapes of draw beads around the part periphery.”
This case study demonstrates how draw beads can help constrain material flow locally during the forming process. In addition, excessive thinning was observed where the vertical wall of the part was deep-drawn. In order to increase the minimum thickness of the drawn part, the blank was trimmed where the flange remains large after forming, to allow the material to flow more readily into the die cavity. At the same time, the blank was optimized by saving 35 percent from the original blank size. The minimum thickness was improved by 10 percent.
“Springback after forming also was investigated,” Ulintz adds. “Less spring- back was observed with proper draw- bead positioning and optimizing the blank profile. An incremental finite- element code was used to conduct finite-element computations to study the forming sequence and springback. The computational results were studied to determine the draw-bead shapes and locations. Then, prototype tooling was used to produce experimental parts to validate numerical results. The com- putation results showed good agree- ment with the experimental results.”
Interested in Learning More
...and attending the two-day con- ference? Visit www.metalforming- magazine.com/diedesign. MF
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44 MetalForming/May 2017
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