Design for stamping manufacturability begins with function

The process of stamping parts—from the initial request for quote (RFQ), through the tooling design/build process, and finally, to the stamping production—can be a long and winding road with a large gap between what is designed and what can be manufactured. A part designed with manufacturability in mind will run the smoothest, with the least amount of downtime caused by tooling design-to-production disconnects.

Of course, many parts do not lend themselves to optimal running conditions for a variety of reasons, and a good tooling house knows many methods to overcome such challenges, but those methods typically add cost to the tool and slow the rate at which the tool can run.

That may be fine and well if the costs of the tooling and part production fit the budget of the end user. However, what if the tooling cost pushes that part out of budget or makes the product price noncompetitive? Which features and dimensional criteria that are adding cost to the part may be unnecessarily complex or overdimensioned?

Function Factors In

Does the customer company have a tooling expert who reviews part designs to ensure that they are designed with tooling feasibility and cost in mind? Does that expert make sure that tolerances are achievable, and that the tool will run efficiently in production? Subtle differences in how a part is dimensioned can make significant differences in tooling and production cost.

The tooling house rarely knows what a part’s function is. Nor does it know the functions of the features within that part. The tooling manufacturer is entirely dependent on the part print to design and build a production tool that will hold required specifications called out on the part print. While that may be how it should be, technically, if a tooling house knows a feature’s function during the tool tryout process—or better yet at the time of RFQ—that can be highly beneficial in wringing out cost and smoothing an operation.

Hole Location Creates Unnecessary Havoc
For example, let’s say a tooling manufacturer is struggling with getting a hole location to check within tolerance on a part because of the inherent nature of the part, combined with a tight block tolerance. After discussing it with the customer, it’s discovered that the hole’s function is simply for hanging the part on a paint line. Had the part designer treated that feature for what it was—a noncritical feature—the part feature tolerance would have reflected that, and it would not have been a problem. The tooling house probably would have been able to quote the project at a lower cost. The tool was likely quoted to account for the difficulty of holding that feature in print, raising the cost of the tool.

Tolerances, Callouts That Are Too Tight
Another example of features that can add cost unnecessarily relates to tolerances. A tool house built a large, relatively complex tool for an automotive Tier 1 stamper. The part design had some rather tight profile callouts on some large flanges. The flange tooling designs included a series of step forms going through the part, which was to be stamped from a light-gauge material.

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