Page 43 - MetalForming June 2011

well as the desire of stampers to con- serve material.
Complex Dies for Stainless Exhausts, Tricky Seat Bracketry
Dilast has carved a nice niche in the automotive supply chain as a special- ist in tooling up metalformers to stamp stainless-steel exhaust components. This niche represents about half of the firm’s book of business. It’s number- two market: complex bracketry for seat- ing assemblies.
Regardless of the end product, Dilast’s tooling almost always is designed to form very complex drawn parts that require simulation to verify formability, supported by design soft- ware that allows for quick turnaround of iterative designs. Dilast employs Aut- oform for simulation, which until recently it had been outsourcing. In April it brought simulation inhouse when it leased an Autoform seat, “giv- ing us more control over design changes,” says Claus, “rather than hav- ing to wait for our supplier to schedule our work.”
The design program of choice at Dilast: Visi Progress, from Vero.
“Visi is very good at allowing us to quickly change radius sizes, and then reblend and change the shape of the form tools,” says Claus. “Time is the critical success factor now, and the costs can rise quickly as delays pile up. Working with stainless steel, we can’t solve springback issues simply by mov- ing a die face a few degrees. The parts and dies are too complex. That’s where continuous improvements made to each Visi release over the years, with the introduction of new software features, play a key role in our success.”
Among the new features of which Claus speaks is target-driven deforma- tion ( TDD), introduced by Vero with Visi Progress V18. Dilast began using Visi in 2003, with V11; it recently reviewed the latest version, V19.
Help with Restrikes, Cam Trims
Target-driven deformation, says Claus, allows him to quickly redesign
features to adapt for springback, based on simulation results. “TDD works quite well with Autoform,” says Claus. “If we’re designing a long part with a lot of form features, and the simula- tion shows we need to redesign to counteract for springback, identified during simulation, we can go back into Visi and quickly remodel features. This can require changing the entire part geometry. Before Vero introduced TDD, this type of complete geometri- cal redo might take an entire day; now we can get it done in an hour, some- times less.”
Claus finds himself redrawing draw radii often, particularly when devel- oping tooling for stainless-steel exhaust parts. “We’re frequently chang- ing radii and the shape of the form tools to adjust material flow,” he says. “Parts are so much more complex than they used to be due to tighter engine compartments—there’s less room and we have to fit parts around other parts. Bends are tighter. And, more parts are undergoing robotic welding, so fitup tolerances are tighter.”
To meet these requirements, Claus notes a trend toward more cam trim- ming in the die, and more restrike sta- tions. “Visi really helps streamline the design process for restrike stations, which are designed precisely to the math model,” he says. “And when developing cam-trim stations, it’s eas- ier to avoid interference problems, and we can see if the parts are nesting properly.”
Target-Driven Deformation in Action
TDD recently saved the day for Claus as he designed tooling to stamp an automotive seat bracket—a saddle- shaped part with a flange. “Remodeling the flange to compensate for spring- back, without affecting the saddle, posed a significant challenge, he notes. “I had to overbend by 3 deg., which required changing the entire part geometry. Using TDD, I remodeled the part in less than an hour.”
While TDD represents a major enhancement to Visi, according to a
software reviewer at Develop3D maga- zine, Vero also has been hard at work refining the software’s user interface. “New features,” writes Al Dean, “include consolidation of the file/open and file import commands...the user has drag and drop access to (several) formats...Visi 18 also brings on board tools for working with mesh data, which may come from a reverse engi- neering process or a simulation. It also provides the tools needed to clean up data, such as for hole filling, rational- izing normals, deleting areas of data and sharpening up edges.”
Claus’s experience proves out Dean’s views. “We’re able to complete design drawings more quickly than ever, with new software features such as automatic view preparation and dimensioning,” he says. “With the last couple of software releases, we’ve been able to reduce detailing time by 50 percent. That’s critical in our mar- ket where time is the critical success factor.” MF
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