Design for Manufacturing (DFM): The Rule New Engineers Break
A part can do its job perfectly and still be a nightmare to make. Where a part's cost really gets decided, the rules each process brings (inside corners, draft, even walls, a bend radius), four moves that make almost any part cheaper to build, and why DFM only works as a conversation held early.
Problem
You design a bracket that does exactly what it should. It's strong enough, it fits the assembly, and on screen it looks perfect. Then the drawing reaches the people who have to make it, and it needs a cutter nobody stocks, five separate setups to reach all its faces, and an inside corner no tool can cut. Nothing about the design is wrong. It was drawn with no idea of how it would be made. And you don't pay for that once: a part that's hard to make costs extra on the first unit and on each one after it, for as long as you build it.
Quick Answer
The short version
Design for manufacturing (DFM) means designing each part with its making in mind, from the very first sketch. It matters because most of what a part will cost over its life is decided on the drawing, long before anyone makes one; by the time the shop gets it, the expensive choices are already made. So you pick the process first and design inside its rules: rounded inside corners for a cutter, tapered walls for a mould, a minimum bend radius for sheet metal. Then four moves pay off on almost any part: fewer parts, standard features, tight tolerances only where they count, and no extra steps after the main operation. And you do it early, with the people who make the part in the room, while a change still costs a conversation instead of new tooling.
Deep Dive
Most of a part's cost is set before anyone cuts metal. The video shows where it gets decided, the rules each process brings, four moves for any part, and why it only works as an early conversation. The map:
