Design for manufacturing and assembly (DFM/DFA)

DFM shapes each part for its process: uniform walls and draft for molding, standard bend radii for sheet metal, accessible features and standard cutters for machining. DFA reduces assembly effort: fewer parts, fewer fastener types, parts that can only go in one way, self-locating features, top-down assembly and simple cable routing.

Most of a product's manufacturing cost is locked in during design, and changing a molded part after its tool is cut is slow and expensive. Early reviews with the intended manufacturer, who knows the process limits and real costs, catch problems while they are cheap to fix.

Where it bites: prototypes made by 3D printing or machining hide problems that only appear in the production process. A design that is easy to prototype isn't necessarily easy to mass-produce.