“When a customer brings us a CAD drawing, one of the first things we do is ask, ‘What is it used for? What is its function?’” Conery relays. “Because as tool designers, we don’t always know what the part is going to be used for at the end of the day. It’s best that we do.” 

Conery offers an example: A customer submitted a drawing with a lance-form slot that is difficult to punch without it being vulnerable to tearing, and problematic also because it would leave very sharp edges. Once he discovered that it was intended for a zip-tie attachment, he redesigned the slots to be punched earlier in the die, coined to smooth the sharp edges, and formed with a less-severe radius. “Then, when they thread the zip-tie through, the feature won’t cut the zip-tie. It’s a better cutting condition for us and a better part for them,” he says.

Bridging the Gulf Between Concept and Reality 

DfM often involves minimizing part complexity to eliminate extraordinary efforts and steps to achieve a feature, saving time and money. 

Successful DfM requires an in-depth understanding of the tool—the die—and its executor—the press—and their respective abilities and limitations. For example, a recurring complaint is that designers using CAD specify unrealistic tolerances—especially unnecessary when the part doesn’t require them. Although another process, such as machining, may consistently deliver tight tolerances, it’s important to remember that delivering very tight tolerances consistently, for thousands or millions of parts, via stamping, is nearly impossible. Just because a hairline can be drawn on a screen doesn’t mean it can translate as a tolerance for a stamped part.

Again, Communication is Key

As often is the case, early conferring is critical to avoid production disasters and the need for Hail Marys. Just as a final production vehicle is not expected to be identical to its former concept self, an initial concept part is not expected to be perfect. It’s okay if the original design needs to undergo refinement and iterations. That’s where toolmakers and tooling engineers ply their experience and expertise. Often, even very small alterations can make a world of difference in transforming a difficult-to-stamp part into a manufacturable one. A slightly wider band, an emboss or a hole moved slightly farther from a bend can prevent wrinkling, tearing, cracking or springback. 

Collaboration among customers and metal formers empowers the DfM process to manifest a streamlined, cost-effective and successful manufacturing operation. MF

Technologies: Software, Tooling

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