The distance between a working prototype and a manufacturable product is rarely visible in a demo. It lives in tolerances, test coverage, supply decisions and documentation—the unglamorous work that determines whether unit one thousand behaves like unit one.
Manufacturing constraints are design inputs
Draft angles, part counts, fastener access, panelization and test-point placement decided late force redesign loops that cost more than the tooling they were meant to protect. The cheapest DFM review is the one held before the first prototype exists.
Design for the worst unit, not the golden one
Prototypes are hand-tuned; production is statistical. Component tolerances, assembly variation and supplier substitutions must be analyzed and budgeted—signal margins, mechanical stack-ups and calibration strategies all need room for the distribution, not the demo unit.
The test plan is part of the product
Every functional claim needs a corresponding factory test that can run in seconds, not minutes. Test fixtures, limits and data logging designed alongside the product—not after it—are what make a production ramp diagnosable when yield dips.
A factory cannot build your intentions. It can only build your documentation.
Transfer is a deliverable, not an event
A manufacturing package—controlled drawings, BOM with approved alternates, assembly and test instructions, quality criteria—is what actually moves to the factory. Programs that treat it as a living deliverable from mid-development transfer in weeks; programs that write it at the end transfer in quarters.